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© Raymond Pettibon 


RESEARCH LIBRARY 
Meiceuehy yy RESEARCH INSTITUTE 


JOHN MOORE ANDREAS COLOR CHEMISTRY LIBRARY FOUNDATION 








PHOTOGRAPHIC FACTS AND FORMULAS 


Books on Photography 


Optics for Photographers, by Hans Harting, Ph. D. Translated by 
Frank R. Fraprie, S. M., F. R. P. S. 232 pages. Cloth, $2.50. 

Chemistry for Photographers, by William R. Flint. 2nd edition. 
218 pages. Cloth, $2.50. 

Pictorial Composition in Photography, by Arthur Hammond. 234 
pages, 49 illustrations. Cloth, $3.50. 

Photo-Engraving Primer, by Stephen H. Horgan. Cloth, $1.50. 

Cash from Your Camera. Edited by Frank R. Fraprie, S. M., F. R. 
P. S. Paper, $1.00. 

Pictorial Landscape Photography, by the Photo Pictorialists of Buf- 
falo. 252 pages, 55 illustrations. Cloth, $4.00. 

Photographic Amusements, by Walter E. Woodbury. 9th edition. 
128 pages, 100 illustrations. Cloth, $1.50. 

Practical Color Photography, by E. J. Wall, F. C. S., F. R. P. S. 
Cloth, $3.00. 

The Air Brush in Photography, by Geo. F. Stine. 143 pages, 45 
illustrations. . Cloth, $2.50. 

Bromoil Printing and Bromoil Transfer, ne Dr. Emil Mayer. 
Translated by Frank R. Fraprie, S. M., F. R. P. S. 199 pages. 
Cloth, $2.50. 

Practical Photography Series, each 50 cents in paper, $1.00 in cloth: 
1. The Secret of Exposure. 2. Beginners’ Troubles. 3. How to 
Choose and Use a Lens. 4. How to Make Prints in Colors. 
5. How to Make Enlargements. 6. How to Make Portraits. 
7. How to Make Lantern Slides. 8. The Elements of Photography. 
9. How to Retouch Negatives. 10. How to Make Good Prints. 
11. Modern Development. 

ENGLISH IMPORTATIONS 

Photography Made Easy, as Easy as A B C, by R. Child Bayley. 
264 pages. Paper, $1.50. 

The Barnet Book of Photography. Cloth, $2.00. 

Art of Retouching Negatives and Practical Directions for Finishing 
and Coloring Photographic Enlargements, by Robert Johnson, 
T. S. Bruce and Alfred Braithwaite. Boards, $2.50. 

Hieroglyphic or Greek Method of Life Drawing, by A. A. Braun. 
Boards, $7.50. 

Photograms of the Year. Paper, $2.50. Cloth, $3.50. 

Penrose’s Pictorial Annual. $4.00. 

Descriptive list on request. 


Published or Imported by 


American Photographic Publishing Co. 


428 Newbury St., Boston 17, Massachusetts 


ie ele 


PHOTOGRAPHIC 
FACTS 


AND FORMULAS 


ey |. WALL. F.C.S., F.R.P.S. 


Associate Editor of 
“AMERICAN PHOTOGRAPHY” 
Author of “Practical Color Photography,” ete. 


! NO 
vat OY 





AMERICAN PHOTOGRAPHIC PUBLISHING Co. 
Boston, Mass.; U.S. A. 
1924 


Copyright, 1924, by 
AMERICAN PHOTOGRAPHIC PUBLISHING CO. 
Entered at Stationers Hall 
Printed and bound in the U.S.A. 
First edition, July, 1924 


The Alpine Press, Boston, Mass., U. S. A. 


INSTITIIre | SEARCH 


Foreword 


The main idea kept in view in the compilation of this 
book has been to provide in condensed form working 
formulas and instructions for the various processes of 
photography. There must necessarily be errors of 
omission and commission, and the publishers will be 
grateful to any reader who, consulting its pages and 
failing to find what he requires, will at once communi- 
cate with them, in order that the omissions may be 
remedied in future editions. Forms for this purpose 
will be found at the end of the book. 

The formulas given have not been selected in hap- 
hazard fashion but, as far as possible, only from credit- 
able sources. 

Certain valuable information, received after the body 
of the book was made up into pages, will be found in 
the Appendix at page 376. 





Contents 


Foreword 

Contents 

Studio and Workroom 
Orthochromatic Photography 
Plate Backing 

Focus and Optics 

Exposure 

Development 

Developers . 

Fixing and Clearing 
Intensification 

Reducers 

Varnishes . : 

Silver Printing Processes 
Printing-Out Papers 

Salted Paper 

Bromide Paper 
Developing-Out Papers ; 
_ Toning Bromide and Gaslight Prints 
Sulphide Toning . 

The Carbon Process 

The Gum-Bichromate Process 


Vii 


123 
130 
141 
150 
160 
173 
189 
199 
204 
216 
234 
249 
255 


Vill CONTENTS 


The Iron Processes 
Platinotype . ; ‘ 
Ozotype and Allied Processes 
Oil and Bromoil . 
Miscellaneous Printing Processes 
Mountants 

Stereoscopic Work 

Lantern Slides - . 

Enlarging - . 

Flashlights: . 

Colour Photography 
Photomechanical Processes . 
Weights and Measures 
Chemical Tables . 

Appendix - . 


Index: . 


258 
274 
295 
302 
314 
325 
328 
330 
334 
339 
344 
351 
360 
368 
376 
377 


Studio and Workroom 


WEIGHTS AND MEaAsurRES.—It will be noted that formulas 
in this work are usually given both in metric and duodecimal 
(or British and U. S.) weights and measures. The metric 
weights and measures are not the exact equivalents of those 
in the other systems; but the ratio of the ingredients in each 
column is the same. Readers must therefore rigidly adhere 
to one or the other system, and not weigh out solids in 
grammes and measure liquids by ounces or a hopeless muddle 
will result. In all cases the conversion has been made on the 
assumption that photographic solutions are measured and not 
weighed out and, therefore, the ratios are based on a uniform 
bulk of 16 oz. or 7680 minims. In many cases fractional 
parts have been omitted or rounded off to the nearest practical 
quantity. In all cases, too, the quantities, 1000 ccm or 16 oz., 
mean that these should be the total bulk of the solution when 
made, unless otherwise stated. Therefore, it is advisable to 
dissolve the dry ingredients in some of the solvent and then 
make up to the given bulk. 

Backcrounps.—Cloth is the best material, and can gener- 
ally be obtained up to 96 inches in width. Calico, bleached or 
unbleached, can be obtained up to 72 inches wide; brown felt 
paper up to 60 inches. Small pieces of cardboard, about 
Y inch square, are required. Lay the stretcher or frame flat 
on the floor, and get a friend to hold the right-hand bottom 
corner of the material down to the corresponding corner of 
the frame, stretch the material quite taut, and nail down the 
top left-hand corner to the edge of the frame. Drive the 
tack or nail through a piece of cardboard and the material at 


l 


2 PHOTOGRAPHIC FACTS AND FORMULAS 


both corners. Then deal with the other corners in the same 
way. Then tack the center of the top and bottom edges, then 
the sides, pulling the material taut before putting in each nail. 
The result should be without any wrinkles. It must then be 
sized. For this rub one part of starch into a cream with” 
three parts of water, and boil until a clear solution is formed. 
Apply this with a stiff brush to the material, and stand the 
frame on end to dry. To make the paint, use: 


Whiting 24 parts 
Powdered glue 8 parts 
Treacle (molasses) 12 parts 
Water 160 parts 


Soak the glue in the water for some time, add the treacle and 
melt with heat, and stir in the whiting until a smooth cream is 
obtained. Divide into three parts. For colours, obtain the 
following dry water colour pigments: ivory black 2 parts, 
ultramarine 1 part, red ochre 1 part. Mix the three pigments 
together and divide into six equal parts; to one third of the 
glue solution add one part of the pigment, to another third 
of the glue add 2 parts of the pigment, and the remainder of 
the powder to the rest of the glue: this will give three dis- 
tempers of different shades. Commercial distemper powders, 
such as kalsomine, may be used. 

Alternatively, dry canvas may be tightly stretched on a 
wooden frame, then well wetted, a mixture of dextrine and 
colour sifted over the surface from a fine sieve, and the 
surface then worked over with a stiff brush. The colours 
used may be as above or any powder colour used for house 
decoration. ‘The colours dry much lighter. For grey and 
black backgrounds, double size, which is used by paper- 
hangers, may be melted in a saucepan, slightly thinned down, 
and drop black and whiting, previously mixed to the required 
tint, added. Two coats should be given with a stiff brush, the 


STUDIO AND WORKROOM o 


second being applied with the brush strokes in opposite direc- 
tion to the first. 

PHOTOGRAPHING MAcHINERY.— Bright parts may be 
dulled by painting over with a thin cream of white lead and 
turpentine, darkened by the admixture of lampblack to give 
a grey. Frequently, dabbing the surfaces with a lump of 
putty will be sufficient. 

MEMORIAL STONES AND BrassEs.—These often present 
considerable trouble, but if the surfaces of the stones are 
swept clean and strong side lighting used, the lettering and 
carvings will be thrown up into better relief. Wetting the 
stone frequently brings out indistinct lettering. In the case 
of brasses, rubbing with whiting, avoiding any deposit in the 
letters, is useful, as is also side lighting. Rubbings, obtained 
by placing a sheet of paper over the brasses and rubbing with 
a soft pencil or charcoal, may also be used. 

SILVERWARE.—Hollow ware may be filled with ice or very 
cold water; then in a warm damp room the outer surface 
will become dewed. Dabbing the surface with putty will 
also kill all reflections. Or the object may be placed inside 
a tunnel of tissue paper, so that the only light reaching it has 
to pass through the paper. 

GLASSWARE.—This may be treated like silver, or hollow 
vessels may be filled with a non-actinic solution. 

Co1ns.—These may be smoked with burning magnesium 
ribbon, which leaves a delicate white film on their surfaces. 
Side lighting is preferable, so as to throw the figures, etc., 
into relief.. An impression may be taken in fine plaster of 
Paris, and this photographed. Or the coins may be placed 
on a fine white calendered card, slightly dampened, with a 
backing of blotting or other soft paper, and passed through 
a copying or other press. This gives an intaglio of the coin, 
which, if lighted with a strong light from the bottom of the 


4 PHOTOGRAPHIC FACTS AND FORMULAS 


design, will when viewed in the usual manner give the impres- 
sion of the relief of the original. 

OBJECTS UNDER GLASs.—If it is desired to show the glass 
cover, give about one fourth of the whole exposure to the 
object with the glass in position; then remove the glass, and 
complete the exposure. 

To BLacken Woop.—Use: 


Borax 62.5 g 1 oz. 
Glycerine 62.5 ccm 1 oz. 
Shellac 125 ¢ 2 oz. 
Water 1000 ccm 16 oz. 


Boil until completely dissolved and add water to make up the 
origiial bulk, then add nigrosine WS, 125 g or 2 oz., stir 
until thoroughly dissolved, and paint the wood two or three 
times. This is not as satisfactory as the following, in which 
the aniline black is chemically formed in the wood: 


Cupric chloride 70g 538 gr. 
Potassium bichromate 70g 538 gr. 
Hot water 1000 ccm 16 oz. 


The wood should be freed from grease, then painted with this 
solution and allowed to dry well, then painted with: 


Aniline hydrochloride 140g 21% 02z. 
Water 1000 ccm 16 oz. 


Allow to dry, wipe off any yellow powder that forms, and 
repaint with these solutions until black enough. As a rule, 
two coats are sufficient, as the colour deepens in a day or two. 
Then rub well with boiled linseed oil and leave to dry. 

To BLAcCKEN Brass.—Use: 


Copper nitrate 208 g¢ 200 gr. 

Water 500 ccm 1 oz. 
Dissolve and add the following solution: 

Silver nitrate 208 g 200 gr. 


Water 500 ccm | 1 oz. 


STUDIO AND WORKROOM S 


Clean the metal thoroughly, immerse in the mixture, and then 
heat; repeat if necessary. Or the following may be used: 


Copper carbonate 50 g 384 gr. 
Ammonia 25 ccm 192 min. 
Water 1000 ccm 16 oz. 


Clean the metal and immerse until black, then wipe dry and 
lacquer. This attacks soft solder. Solution of antimony 
(butter of antimony), brushed on, gives bronze colours. It 
has been stated that boiling the metal in a solution of potas- 
sium sulphide (liver of sulphur) until sufficiently black, then 
rinsing, drying and smearing a little oil over it, gives better 
results than the above silver method. 

FIREPROOFING FABRICS.—Soak in: 


Alum 80 g 8 oz. 
Ammonium carbonate 25¢ 2Y4 oz. 
Boric acid I5¢ LY oz. 
Borax , ates 134 oz. 
Water 1000 ccm 100 oz. 
Cor 
Boric acid llg 200 gr. 
Ammonium phosphate 100 g 4 oz. 
Water 1000 ccm 40 oz. 
Crt 
Borax 150g LZ OF. 
Magnesium sulphate $2 Sor 9 oz. 
Water 1000 ccm 80 oz. 
Starch Zao Z071 


Boil the starch with the water and add the salts. Immerse 
the fabric until thoroughly soaked, then dry and iron. Or a 
strong solution of aluminum acetate, sp. gr. 1.050, diluted 
with 40 times its volume of water, may be used. The material 
should be immersed for 24 hours and then dried in the shade. 


6 PHOTOGRAPHIC FACTS AND FORMULAS 


FLEXIBLE LANTERN SCREEN.—Take: 


Glycerine 16 parts 
White glue 16 parts 
Zinc oxide 32 parts 
Hot water 10 parts 


All are to be weighed. Dissolve the glue in the hot water and 
add the zinc oxide, ground up with the glycerine. Apply hot 
to the screen. A screen 10 feet square requires about 160 
ounces, 

To BLackEN ALUMINUM.—Clean perfectly free from 
grease by washing in soda solution, wash well, and immerse 
in: 


Ferrous sulphate 1 part 
Arsenious acid 1 part 
Hydrochloric acid 12 parts 
Water 12 parts 


When the colour is deep enough, dry with fine sawdust, and 
lacquer. This solution is intensely poisonous. 

BLACK FOR CAMERAS.—This may be used for wood or 
leather, inside or out: 


Nigrosine, spirit soluble 2512 37 pr. 
Bismarck brown 0.65 g 10 er. 
Denatured alcohol or 

methylated spirit 3.0 ccm 50 min. 
Aniline. 29 ccm 1 oz. 


Heat the dyes with the alcohol until dissolved, and then add 
the aniline; apply with a brush and dry before the fire or in 
the sun. Or, for a dead matt varnish, lampblack may be 
rubbed up with gold size or shellac varnish, using as little of 
the liquid as possible; then thin down with turpentine. 

INK FoR BottLes.—The following formula gives a water- 
proof ink, and either black or white ink can be made by using 
lampblack or zine white. 


STUDIO AND WORKROOM 7 


Copal, powdered I2¢ 90 gr. 

Oil of lavender 1000 ccm 16 oz. 
Dissolve by heat and stir in, for black: 

Lampblack ery 9 gr. 

Indigo 0.5¢ 4 er. 
Or, for white: 


Zinc white lig 11 gr. 
Apply with a fine brush. : 
Mattinc Giass.—Dissolve by heat : 


Sodium or potassium fluoride 4¢ 20 gr. 
Gelatine 4¢ 20 gr. 
Water 1000 ccm 1 oz. 


Coat on the glass and allow to set well and dry, then immerse 
in a 6 per cent solution of hydrochloric acid for 30 to 60 
seconds, and dry without washing. The gelatine can be dis- 
solved off with hot water and a fine matt surface is obtained. 
Or the following may be used: 


A. Sodium fluoride 60 g 60 gr. 
Potassium sulphate 12¢ 12 gr. 
Water 500 ccm | 1 oz. 

B. Zinc chloride l4g 14 gr. 
Hydrochloric acid 65 ccm 65 min. 
Water 500 ccm Loz: 


Mix in equal quantities just before use and apply with a quill 
pen or fine brush. In about 30 minutes a fine matt surface is 
obtained. Another plan, which is even more convenient, is 
to paint a square or rectangle with the above solution, when 
the whole surface will be matted. Titles may easily be writ- 
ten on the surface with a soft lead pencil, and can be easily 
removed at any time with rubber or soap and water. 
SUBSTITUTES FOR GRoUND GLAss.—Expose a dry plate to 
the light of a match at a distance of 3 feet, then develop until 
uniformly grey, fix and wash. Immerse the plate in a solu- 


8 PHOTOGRAPHIC FACTS AND FORMULAS 


tion of iodine in potassium iodide, or a few drops of tincture 
of iodine in water, until the grey fog turns yellow; then 
rinse, immerse in weak ammonia water until it turns white, 
wash and dry. The longer the plate is developed in the first 
place, the more pronounced becomes the mattness. Asa rule, 
this gives a surface that is only useful with a magnifier, the 
grain being too fine for ordinary visual work. Or the follow- 
ing may be used: 


Rice starch 20 parts 
Water glass 100 parts 
Water 200 parts 


The water glass is the ordinary commercial solution of 
sodium silicate of 1.3 sp. gr. Mix the above by first rubbing 
the starch up with the water and then adding the silicate. 
Level the glass and pour enough of the solution on to cover 
it, allow to dry, then coat with celluloid varnish. 

To CLean Giass.—Immerse the glass in the following: 


Potassium bichromate 50 g 1 oz. 
Sulphuric acid 25 ccm VY o7z. 
Water 1000 ccm 20 oz. 


Immerse the glass and scrub with an old toothbrush or mop 
made by tying some rags on a stick, turning the glasses over 
with a stick, as the solution bites the fingers. Rinse in cold 
water, then in hot water and dry. Or make a thin cream of: 


Tripoli 500 g 8 oz. 
Denatured alcohol or 

methylated spirit 500 ccm 8 oz. 
Ammonia 500 ccm 8 oz. 


Rub well with a swab of cloth and polish with a clean cloth, 
finishing with filter paper. 

CeEMENTS.—Melt rubber and shellac in equal parts on a 
sand bath and apply to the warm glass or metal. This is 
useful for cementing glass to glass, or glass to metal. Or 


STUDIO AND WORKROOM 9 


glycerine and finely powdered litharge may be worked into 
a thick paste; the broken edges should be painted with 
glycerine, then the paste applied, and the articles bound to- 
gether with string and left for a day or two. Or zinc oxide 
should be worked into a stiff paste with a 15 per cent solution 
of zinc chloride. Or: 

Sulphur flowers 72 parts 


Pale resin 40 parts 
Shellac 10 parts 
Mastic 20 parts 
Crude lac 20 parts 


Barium sulphate 60 parts 
Melt the gums by heat and add the sulphur, stir well and then 
add the baryta. This must be melted each time before use. 

DIAMOND CEMENT.—Dissolve gelatine to saturation in 
glacial acetic acid. This must be melted on a water bath 
before use. 

DAmpP-PROOF GLUE.—Cover some good glue with water 
and allow to soak for 12 hours, drain off the water, melt the 
glue by heat, and add one-fourth its volume of linseed oil. 

MarInE GLUE.—Dissolve india rubber shreds in benzole 
1 part, shellac 2 parts; or ordinary cycle tyre cement may be 
used, one-fourth its volume of shellac added, and melted by 
heat. The vapour of this is very inflammable. 

Liguip GLuE.—This should not be used for mounting 
photographs : 


Fine glue 800 g 8 oz. 
Water 1000 cem 10 oz. 
Allow to soak for 24 hours, then melt by heat, and add: 
Nitric acid, strong 175 ccm 134 oz. 


SILVERING GLass.—Brashear’s Process modified, as used 
at the Royal Observatory, Greenwich, England. The follow- 


10 PHOTOGRAPHIC FACTS AND FORMULAS 


ing solutions are required: A. 10 per cent silver nitrate solu- 
tion; B. 25 per cent ammonia solution; C. 10 per cent caustic 
potash solution; D. reducing solution as follows: 


Sugar 90 g 690 gr. 
Nitric acid 4 ccm 30 min. 
Alcohol 175ccm 202z., 380 min. 
Water 1000 ccm 16 oz. 


To make this, dissolve the sugar and acid in the water, boil 
for 15 minutes, cool down, and add the alcohol. The longer 
this solution has been made, the better it works. The actual 
silvering bath is made up as follows: 


A solution 20 ccm 340 min. 
B solution (more or less) 10ccm 170 min. 
C solution 10 ccm 170 min. 
D solution 5 ccm 85 min. 
Distilled water 100ccm 30z., 250 min. 


To prepare the bath for about 700 square inches of glass 
surface, take 1200 ccm (42 oz., 112 min.) of A, and add B 
until the solution nearly clears up, which will take about 
500 ccm (17 oz., 287 min.) ; then add C 600 ccm (21 oz., 
56 min.). The mixture will again become thick; then add 
cautiously more B until the solution clears. It should now be 
a brown colour but transparent. Then add: 

Distilled water 6000 ccm 211 0z., 84 min. 

D solution 300ccm 10 02z., 268 min. 
The temperature should be from 18° to 21° C. (65° to 
70° F.). With lower temperatures the D solution must be 
slightly increased. Too low temperatures give too thin films, 
while with too high temperatures the silver film is too soft. 
The glass should be covered with water, and, if the solutions 
are mixed beforehand, the water should be poured off and 
the silvering liquid at once applied; but good results are 
obtained by pouring off the water, pouring on the D solution, 


STUDIO AND WORKROOM 11 


rocking the dish, and then adding the silver-potash mixtures. 
The action begins at once, and in 2 or 3 minutes a light swab 
of absorbent cotton should be lightly drawn over the surface 
so as to prevent the heavy sediment from settling down. As 
the cotton becomes dirty, it should be thrown away and fresh 
used. When to stop the action depends entirely upon experi- 
ence; if too soon, the deposit is thin, and if too prolonged, it 
is thick and requires much polishing. Wash with distilled 
water, lightly swab with cotton, and allow to dry in a vertical 
position for at least an hour. Polishers are most satisfactorily 
made of the best chamois leather stretched over a ball of 
cotton. Two polishers are necessary. First go over the 
whole surface with a plain rubber with light circular strokes, 
dusting occasionally. Then rub a little rouge into the other 
pad, and polish in the same way. 

It has been stated that celluloid can be silvered with the 
above solution ; or the celluloid may be immersed in the sugar 
solution and then the others added in succession. For the 
above process the old fashioned sugar candy is the best form 
of sugar to use; if this is not procurable, the best cane sugar 
must be used. 

Rk. E. Crowther gave a modification of this process in which 
caustic soda is used and which seems not to be so dependent 
on absolute purity of the chemicals. To make 100 ccm (3 oz., 
250 min.) of solution, the following are required: I. 10 
per cent solution of silver nitrate in distilled water; II. 7.25 
per cent solution of caustic soda in distilled water; III. 28 to 
30 per cent ammonia solution (strongest ammonia water) ; 
IV. Reducing solution—equal volumes of A and B, made as 
follows: 

A. Sugar,lump or whitecrystal 9g 150 gr. 
Distilled water 50 ccm 845 min. 
Nitric acid, c. p. 0.4 ccm 6 min. 


12 PHOTOGRAPHIC FACTS AND FORMULAS 


Alcohol 17 ccm 285 min. 
Distilled water to 100ccm 302z., 250 min. 
B. Sugar 10g 165 gr. 
Distilled water 50 ccm 845 min. 
Tartaric acid, cryst. lg 15.4 gr. 
Boil for 5 minutes, cool and add: 
Alcohol 18 ccm 304 min. 
Distilled water to 100ccm 30z., 250 min. 


For every 100 ccm silvering solution take: 11 ccm solution I. 
(186 min.), remove 4 ccm (68 min.), and dilute with 15 ccm 
(250 min.) distilled water; add to the 7 ccm, while shaking, 
ammonia III., until just clear; then, while shaking, add 10 
ccm (169 min.) solution II., and again, while shaking, add 
enough ammonia to just redissolve the precipitate. Finally, 
add the diluted 4 ccm of solution I., obtaining a sherry- 
coloured, opalescent liquid. Filter and dilute to 78 ccm 
(2 oz., 358 min.). Mix 11 ccm (186 min.) of IV. with 
11 ccm distilled water, add to the sherry-coloured silver solu- 
tion, and pour immediately on the glass, which should be 
from 3° to 6° C. (5° to 10° F.) warmer than the solution. 
Rock vigorously, and silver for two and a half times the time 
observed from pouring on the mixed solutions until deposi- 
tion commences. Rinse twice in distilled water, swab under 
a tap, blot off the surface water, allow to dry half an hour in 
a warm place, and polish off the slight bloom. 

The Rochelle Salts Process—Two solutions are required 
for this: 


A. Silver nitrate 10¢g 77 gr. 
Distilled water 1000 ccm 16 oz. 
B. Silver nitrate 2¢g 15.4 gr. 
Rochelle salts 1.66¢ 12-5'ee! 
Distilled water 1000 ccm 16 oz. 


In making this solution the water should be brought to a boil, 


STUDIO AND WORKROOM 13 


and first the silver and then the Rochelle salts added, both 
being dissolved in as small a quantity of boiling distilled 
water as possible. Boiling should be continued for about 25 
minutes, until a grey powder has collected at the bottom of 
the flask. The liquid should then be at once filtered until 
quite clear, and it may be necessary to repeat this three or 
four times. The longer the boiling the more rapid the 
deposition of the silver, and the more uniform it will be. 
Perfectly prepared solutions will keep for about a month. 
Equal volumes of the two solutions are mixed just before use. 
The Formaldehyde Process (Lumiére)—Clean the glass 
thoroughly with nitric acid, and wash well with distilled water. 
Pour on the surface a 25 per cent solution of alcohol and 
leave for a few minutes. Prepare the following solution, 
which must not be made until required for use: 
Formaldehyde, 40% solution 24 drops 24 drops 


Alcohol, 90% 24 ccm 407 min. 
Distilled water 24 ccm 407 min. 
Silver solution 48 ccm 812 min. 


This is sufficient for 1000 qcm (155 sq. in.), and the tempera- 
ture should be from 16° to 20° C. (60° to 68° F.). The 
silver solution is prepared as follows: 

Silver nitrate 10 ¢g 77 gr. 
Distilled water 100 ccm A07- 
Add solution of ammonia drop by drop until the brown 
precipitate first formed is redissolved; but extreme care must 

be taken not to add too much ammonia. Then add: 

Silver nitrate aS 15.4 er. 
Distilled water 100 ccm Z0z. 
Then add sufficient water to make the total bulk 1000 ccm 
(16 oz.), and filter several times until quite clear. The glass 
should be drained from the alcohol bath and immediately 
covered with the silvering solution. The deposition begins in 


14 PHOTOGRAPHIC FACTS AND FORMULAS 


about 90 seconds and will be complete in about 2 minutes. 
During the silvering, the bath should be gently rocked to 
prevent striz. As soon as the liquid begins to become cloudy 
or show spicules of silver, it should be poured off and a 
second quantity of solution applied. Several coatings may 
be thus applied until the desired thickness is obtained. At 
the close of the operation the surface has a slightly reddish- 
brown appearance. It should be washed with successive lots 
of distilled water and dried, standing it on white blotting 
paper. When the film is perfectly dry, it can be polished 
with a soft chamois, enclosing a pad of absorbent cotton and 
rouge; the rouge used for gold is the best. The alcohol is 
used to prevent the formation of a precipitate in the solution, 
and, if this forms, too much formaldehyde has been used. 
If too little formaldehyde be used, the film has a pronounced 
reddish-brown colour and is punctuated with numerous pin- 
holes. In all cases, the formaldehyde must only be added 
just before applying the mixture to the glass. If too high a 
temperature be used, the deposit forms too rapidly and be- 
comes powdery. For small mirrors, the glass may be placed 
in a dish of porcelain or glass, and the alcohol bath may be 
omitted. If, instead of using the silvered surface as the 
mirror, the glass side is used, then the silver coat should be 
covered with: 


Gum dammar 10¢g 77 ot. 
Bitumen of Judea (asphalt) 100¢ 770 gr. 
Red ochre 200 g 3 1/5 oz. 
Benzole 1000 ccm 16 oz. 


The ammoniacal solutions of silver are dangerous to keep in 
stock, as they may form fulminating silver which is explosive. - 

LinE DRAWINGS FROM PRINTS.—Waterproof drawing ink 
should be used in drawing over any desired part of the print; 
then immerse it in: 


STUDIO AND WORKROOM 


Iodine 0.5 g 
Potassium cyanide 0.03 g 
Water 1000 ccm 


15 


3.84 gr. 
0.25 er. 
16 oz. 


Rub the cyanide up with the iodine, add first a very little 
water, and then make up to bulk. Or the following may be 


used : 
Thiocarbamide Loe 
Nitric acid to com 
Water 1000 ccm 
Or: 
Potassium bichromate 8g 
Sulphuric acid 12 ccm 
Water 1000 ccm 


Then wash well. 


119 gr. 
119 min. 
16 oz. 


62 gr. 
90 min. 
16 oz. 


NecaTives Direct.—This method may be used for direct 
or enlarged prints on paper or plates. The image should be 


developed with: 


Amidol 6.25 g 
Sodium sulphite, dry 15.6¢ 
Ammonium bromide 4.75 ¢ 
Potassium metabisulphite 2g 
Water 1000 ccm 


45 er. 
120 er. 
36 gr. 
tier, 
16 oz. 


Development should be stopped when the image is seen 
through at the back of the plate. Wash for 5 minutes, back 
with a piece of wet black paper, and expose to daylight for 
30 seconds or to 6 inches of magnesium ribbon held one foot 


from the plate. Bleach in: 


Potassium bichromate 29.3 ¢ 

Nitric acid 12 ccm 

Water 1000 ccm 
Then immerse in: 

Sodium sulphite, dry 95 g 


Potassium metabisulphite 6.25 g 


225 ef. 
90 min. 
16 oz. 


1¥Z oz. 
45 gr, 


16 PHOTOGRAPHIC FACTS AND FORMULAS 


Water 1000 ccm 16 oz. 
This clears the bichromate stain; after the plate has been 
well washed, develop in the developer given above without 
the bromide. 

Liguip SAFELIGHTS.—Sometimes cells filled with liquid 
are used in front of the light, but they present no particular 
advantage. The following have been recommended: 

Deep orange (Farmer) : Potassium bichromate 6 per cent 
solution in 3@ inch thickness. This is only suitable for 
ordinary plates. 

Or (Davenport) : 


Mandarin orange 20 g 154 gr. 

Water 1000 ccm 16 oz. 
Or (Wordsley) : 

Eosine 0.13 g 0.1 gr. 

Metanil yellow 3.2¢ Zber: 

Water 1000 ccm 16 oz. 
Or, for a darker filter: 

Eosine . 0.4¢ 3 gr. 

Metanil yellow 2.6¢ 20 er. 

Water 1000 ccm 16 oz. 
Or (Davenport) : 

New coccin 2¢g 15.4 gr. 

Water 1000 ccm 16 oz. 
For deep red in 1 inch thickness: 

Tartrazine 0.5 g 3.8 gr. 

Violet Dahlia BO 0.2 ¢ 1S ee 

Water 1000 ccm 16 oz. 
Ons 

Naphthol yellow S lg (ieee 

Violet Dahlia BO 0.18 g 1.38 gr. 


Water 1000 ccm 16 oz. 


STUDIO AND WORKROOM 17 


Liquid green filter: 


Acid green 0.6¢g 4.6 gr. 
Naphthol green 0.62 4.6 gr. 
Tartrazine 15g 11.5 gr. 
Water 1000 ccm 16 oz. 


The water in the above formulas is apt to evaporate, and this 
trouble may be overcome by using glycerine instead. 

Tartrazine 0.05 per cent solution absorbs to wave-length 
510. Potassium bichromate 10 per cent solution absorbs to 
550. The same solution plus 0.1 per cent of fuchsine to 620; 
with 0.2 of fuchsine to 630; with 0.5 per cent fuchsine to 
635; with 0.2 per cent acid violet to 645. Tartrazine 0.05 per 
cent solution plus 0.02 per cent methyl violet to 660. Thick- 
ness of liquid in all cases 10 cm. For a green light with a 
liquid thickness of 214 cm, use: 


Blueish acid green 0.625 g 4.8 er. 
Naphthol green 0.075 g 0.576 er. 
Tartrazine 0.045 g 0.35 gr. 
Water 1000 ccm 16 oz. 


In course of time, the water evaporates from the heat of the 
lamp. This can be obviated by using glycerine as the solvent 
instead of water. 

GLass SAFELIGHTS.—Coloured glasses, or glass coated 
with gelatine stained with dyes, are best for illumination of 
the darkroom. The most satisfactory method of making 
the latter is to add a definite quantity of dye to a given 
quantity of gelatine solution and allow a definite quantity per 
area. Soft gelatine is the most suitable, and either a 6 or 8 
per cent solution should be made. Weigh out the gelatine and 
cover with water, stir for about 5 minutes and pour the 
water off, and repeat this three times; finally, drain off as 
much water as possible, melt the gelatine in a water bath, and 
add enough water to make up to bulk. The temperature 


18 PHOTOGRAPHIC FACTS AND FORMULAS 


should be about 60° C. (140° F.), and the dye added, prefer- 
ably, in solution. The glass should be levelled, the necessary 
quantity of the dyed gelatine coated on it, allowed to set and 
dried. Yellow screens, suitable for bromide papers and 
lantern slide work: 

Tartrazine 8g 62 gr. 
Gelatine solution, 8% 1000 ccm 16 oz. 
Allow 7 to 10 ccm to 100 qcm, or 750 to 1000 minims per 
100 sq. in. Two such glasses should be bound up together. 

Orange: 
Rose Bengal 3g 23 gr. 
Gelatine solution, 8% 1000 ccm 16 oz. 
Use the same quantity as above, and bind one of these red 
screens with one of the yellow tartrazine ones. 
Bright red: 
Xylene red 8g 62 gr. 
Gelatine solution, 8% 1000 ccm 16 oz. 
Use the same quantity and bind with one of the tartrazine 
screens. 


Deeper red: 
Crystal violet, 4% sol. 8 ccm 62 min. 


Gelatine, 8% - 1000 ccm 16 oz. 
Use as above with a tartrazine screen. 
Bright red (Hubl): - 


Fast red 5g 3814 er. 
Tartrazine 5g 384 gr. 
Gelatine, 8% sol. 1000 ccm 16 oz. 


Allow 7 ccm per 100 qcm, or 750 minims per 100 sq. in. 
This cuts out all light to 600, and is safe for all ordinary 
plates. 
Deep red (Hubl): 
Crystal violet 1.65 ¢ Zier 
Cupric sulphate 8.25 g 63 gr. 


‘STUDIO AND WORKROOM 19 


Glacial acetic acid 16 drops 8 drops 
Gelatine, 6% sol. 1000 ccm 16 oz. 
Allow the same quantity as above, and bind up with one of 

the bright red screens. Or: 


Tartrazine Toe 57) gr. 
Crystal violet 15.5 g 120 gr. 
Cupric sulphate : 1/25.2 ovo OT: 
Glacial acetic acid 15 drops 8 drops 
Gelatine, 8% sol. 1000 ccm 16 oz. 


Use the same quantity as above. This cuts out to 630 and is 
safe for orthochromatic plates. 

GREEN SAFELIGHTS.—These are used for panchromatic 
plates, and are occasionally adopted instead of the red, for 
with a green light it is possible to see better than with a faint 
red. Hubl recommended a combination of filter blue with 
naphthol green, which is the only green dye that cuts out the 
extreme red. The blue was made into a stock solution of : 


Filter blue 0.1 g 0.77 gr. 

Water 1000 ccm 16 oz. 

Ammonia 1 ccm Ff BY. 
For the screen use: 

Naphthol green 8g 61 gr. 

Blue solution as above 32 ccm meteor 

Gelatine, 8% sol. 1000 ccm 16 oz. 


Allow 7 ccm per 100 qcm, or 750 minims per 100 sq. in. 
Or (Lowy): 


New Bordeaux R ji20 2 20 or. 
Tartrazine 6g 46 er. 
Light green S 9g 69 gr. 
Glycerine 50 ccm 384 min. 
Gelatine, 8% sol. 1000 ccm 16 oz. 


Allow about 10 ccm per 100 qcm, or 1000 minims per 100 
sq. in. 


20 PHOTOGRAPHIC FACTS AND FORMULAS 


Old fixed-out dry plates, or negatives freed from their 
images by reduction, may also be used by soaking in the 
above dye solutions minus the gelatine, that is, using water 
instead of the gelatine solution, for half an hour, then rinsing 
and drying. Or soak one plate in 3 per cent solution of 
naphthol yellow, and another in 0.9 per cent solution of 
methyl violet for half an hour, rinse, dry and bind together. 
The following was suggested by Haberkorn: 


Gelatine 60 g 460 er. 

Water 1000 ccm 16 oz. 
Soak for 30 minutes, melt on water bath, and add: 

Blueish acid green l5¢ TiS 'aie 
Then add: 

Tartrazine 0.18 g 13.8 gr. 

Naphthol green 0.4¢ A Pe Bs 


Stir well and filter while hot. To every 100 qcm allow 7 ccm, 
or 750 minims per 100 sq. in. Bind two such screens together, 
and coat one with matt varnish, or use tissue paper between; 
a sheet of ground glass placed between the light and the 
screen absorbs some of the heat. 

NON-ACTINIC PAPER.—Soak the paper in: 


Tartrazine 10¢ 77. Bt. 
Rhodamine lg POE fac 
Water 500 ccm 8 oz. 
Alcohol 500 ccm 8 oz. 


The quantity of rhodamine may be increased at will, when a 
deeper coloured paper will be obtained. The above paper is 
safe for rapid ordinary plates. Translucent vegetable parch- 
ment paper was also suggested. This was to be immersed 
for 5 minutes in a warm 10 per cent solution of gelatine and 
dried, then stained up in one of the following baths: 

A. Tartrazine 2 per cent solution 

B. Chrysoidine 0.1 per cent solution 


STUDIO AND WORKROOM 21 


C. Blue carmine 1.0 per cent solution 

D. Methyl violet 0.1 per cent solution 
A gives a bright yellow paper, and one thickness is suitable 
for development papers. Two sheets of B and one of A 
are suitable for bromide papers and slow plates. Two of C 
and one of A are suitable for panchromatic plates, if not too 
bright a light be used; another A makes it safer. One of A 
and one of C may be used for ordinary and orthochromatic 
plates (Namias). 

A.LcoHoL.—In several formulas “alcohol” is recommended 
as an ingredient, although under the prohibition act it is 
impossible for the average person in the United States to 
obtain this in any legal manner. In some cases ordinary 
denatured alcohol may be used, but in others as, for instance, 
the colour-sensitising of plates, this is worse than useless 
because it has a very prejudicial effect on the emulsion. It 
is possible to obtain from chemical and bacteriological supply 
houses pure methyl alcohol under the names of Eagle 
methanol, or Columbian methanol or spirits, or methyl alco- 
hol C. P., and these may be substituted in nearly every case. 


Orthochromatic Photography 


WAVE-LENGTHS OF THE PRINCIPAL FRAUNHOFER LINES. 


Fraunhofer line Wave-length Colour 
A 7594 
a 7186 Red 
B 6867 
C 6563 Bright red 
D, 5896 Yellow-orange 
D, 5890 
E 5270 Green 
b, 5184 
b, 5173 
b, 5169 
b, 5168 
F 4861 Bright blue 
G 4308 Indigo blue 
g 4227 
h 4101 
‘acy 3968 Violet 
H, 3960 Violet 
K 3934 Ultra-violet 
D 3821-3816 Ultra-violet 
M 3728 Ultra-violet 
N 3581 Ultra-violet 
O 3441 Ultra-violet 
P 3361 Ultra-violet 
O 3287 Ultra-violet 
R 3180 Ultra-violet 
S 3100 Ultra-violet 
ct 3021 Ultra-violet 
U 2948 Ultra-violet 


22 


ORTHOCHROMATIC PHOTOGRAPHY “0 


The wave-lengths in the above table are those given by 
Rowland, and are usually employed, but for extreme accu- 
racy in spectroscopic work corrections must be used. The 
unit of measurement is Angstrom’s unit, one ten millionth of 
a millimeter or A. U. (called also tenth meter, t. m.), and 
only round numbers are given; thus, taking the red cadmium 
line, it would be called on the above plan 6438, while its 
correct measurement is 6438.4722. It is frequently the 
custom to employ other units, for instance, the millionth of 
a millimeter my is used, or the thousandth of a millimeter p 
(pronounced mu). Thus the cadmium line may be expressed 
as: 6.4384722 x 10-° cm, or 0.64384722 yp, or 643.84722 py 
or mp, or 6438.4722 A. U. or t. m. It is usual in photo- 
graphic literature to use the abbreviated A. U., as 6438 or 
the still briefer designation 644. The Greek lambda or A is 
used to designate the wave-length. 

It is very frequent also to designate a colour or position in 
the spectrum by such a term as D 4 C, which means half way 
between the lines D and C; this would mean, taking 5893 as 
the mean wave-length of the D lines, that the stated position 
would be half the distance or difference of wave-lengths, thus 
C 6563 — 5893 = 670, then 670 divided by 2 plus 5893 = 
6228, the designated wave-length. 

DISTRIBUTION OF COLOURS IN THE SPECTRUM.—Various 
tables of the distribution of the colours in the spectrum have 
been given, but the following compiled by Listing may be 
accepted as being typical: 


Colour Wave-length 
End 819 
Deep red Middle 768 
End 723 
Red Middle 683 


End 647 


24 PHOTOGRAPHIC FACTS AND FORMULAS 


Orange Middle 614 
End 585 
Yellow Middle 559 
End 534 
Green Middle 512 
End 491 
Cyan blue Middle 473 
End 455 
Indigo Middle 439 
End 424 
Violet Middle 409 
End 396 
Lavender Middle 384 
End 32 


ORTHOCHROMATISING PLATES.—Ordinary, or non-colour 
sensitive plates, may be orthochromatised by bathing in solu- 
tions of dyes. As a rule, such plates have a higher colour 
sensitivity than those coated with an emulsion to which the 
dye is added during the mixing, but they do not keep quite 
as well. 

Blue-green and Green Sensitisers Acridine orange NO, 
made by Leonhardt of Muhlheim, was the old dye used. A 
saturated alcoholic solution was made and diluted with water ; 
but this dye stains the gelatine so tenaciously that it cannot 
be removed except with an alcohol bath. It has been entirely 
replaced by pinaflavol (Hoechst) or the new dye dimethyl- 
styrylpyridine methiodide, suggested by Mills and Pope. This 
is used in an aqueous solution, 1:30,000 or 1:40,000, in 
which the plates are bathed for 3 minutes, rinsed and dried. 
This gives very even sensitiveness from the bright blue to the 
yellow at 560, then falling off rapidly to 620, and without the 
usual gap in the blue-green, characteristic of the eosine dyes. 

Green and Yellow Sensitisers——Erythrosine is the dye 


ORTHOCHROMATIC PHOTOGRAPHY 25 


generally used. The extra blueish kind should be used in a 
1:5000 aqueous solution with the addition of 0.5 per cent 
of ammonia. This gives a strong yellow, orange and green 
sensitiveness, but a marked want of sensitiveness in the blue- 
green. For this reason the new dyes mentioned above may 
be substituted with advantage, but the proportion of ammonia 
should be reduced to one-tenth. 
- Green, Yellow and Orange Sensitisers—To obtain sensi- 
tiveness up to 620 to 640 in the orange, any of the following 
dyes may be used: isocol (Bayer), orthochrome T, pina- 
verdol (Hoechst), sensitol green (Ilford), or pinachrome 
(Hoechst). These should be used in about a 1: 50,000 solu- 
tion, with the addition of a little ammonia, not more than 
0.01 per cent. The plates should be bathed for 3 or 4 
minutes, then rinsed in alcohol, and dried as quickly as pos- 
sible. Instead of using ammonia in the bath, it is preferable 
to use about 0.02 per cent of borax, which does not tend to 
give so much fog. The dilute dye solutions have a tendency 
to deposit a flocculent precipitate, and this can be prevented 
by adding from 20 to 40 per cent of ethyl or methyl alcohol 
or acetone to the bath, but this method does not give such 
good colour sensitiveness as with aqueous solutions. A deep 
red safelight may be used until the plates are covered with the 
dye solution, and then the rest of the operations should be 
conducted in darkness, or a green safelight used. 
Panchromatic and Red Sensitisers—Pinacyanol (Hoechst) 
or sensitol red and sensitol violet (Ilford) may be used for 
red sensitising and panchromatic plates, the violet dyes giving 
the best all round results; though a mixture of orthochrome 
or sensitol green with the violet may be used, in the ratio of 
2 of the former to 1 of the latter. The total strength of the 
bath should not be more than 1:75,000. Ammonia or borax 
should be used in the same way and the same precautions 


26 PHOTOGRAPHIC FACTS AND FORMULAS 


taken as to the use of a green safelight. These dyes sensitise 
to about 720. For the extreme red and infra-red, dicyanine 
must be used. This does not sensitise for green at all, and 
great care must be taken in protecting the dye and its solution 
from light. 

Only perfectly clean glass dishes should be used for bath- 
ing plates; old porcelain dishes and metal tanks are to be 
avoided, as, in the former case, they are apt to contaminate 
the dye baths from traces of old solutions held in the cracks, 
and metals tend to reduce the dyes and cause fog. Home- 
bathed plates will not keep well, and the sooner they are used 
the better. 

The following method of hypersensitising plates gives 
extraordinary colour sensitivity and speed, but the plates will 
not keep more than about 36 hours. Three stock solutions of 
dyes are required: 


A. Pinaverdol lg 7.68 gr. 
Alcohol, 90° 1000 ccm 16 oz. 
B. Pinachrome 0.05 g 0.384 gr. 
Alcohol, 90° 1000 ccm 16 oz. 
C. Pinacyanol 0.05 g 0.384 gr. 
Alcohol, 90° 1000 ccm 16 oz. 
D. Solution A 405 ccm 634 oz. 
Solution B 405 ccm 634 Oz. 
Solution C 210 ccm 34 02. 


If absolutely correct rendering of the colours is required, the 
ratios of these solutions may have to be altered slightly. It 
will be understood also that the English dyes, sensitol green 
and sensitol red, may be used instead of the pinaverdol and 
pinacyanol with equally satisfactory results. Stock dye solu- 
tion: | | 
E. Stock solution D 400 ccm 60z., 192 min. 
Alcohol 600 ccm 9o0z., 288 min. 


ORTHOCHROMATIC PHOTOGRAPHY Las 


F. Silver chloride 2¢ 1.54 gr. 
Ammonia, 22° 80 ccm 61 min. 
Distilled water 920 ccm 16 oz. 


The ammonia should have a specific gravity of about 0.92. 
Sensitising bath: 


G. Solution E 100 ccm 1 o0z., 288 min. 
Solution F 100ccm 1 oz., 288 min. 
Alcohol, 22.5° 800 ccm 13 oz. 


This alcohol contains approximately 50 per cent water. The 
plates should be bathed at as low a temperature as possible, 
the dish rocked for 3 minutes, the plates rinsed for 1 minute, 
and then dried as rapidly as possible. It is possible to take 
snapshots with plates thus bathed in well-lighted rooms with 
a lens working at f: 4. 

Various formulas have been given for panchromatising 
plates, some of which are given here. As a rule, the fastest 
plates should not be used, as they are more liable to fog on 
keeping; and a clean working plate should be chosen. 

Wallace’s Bath. 


Pinacyanol 15 ccm. 115 min. 
Pinaverdol 12 ccm 92 min. 
Homocol 12 ccm 92 min. 
Ammonia 35.7 ccm 270 min. 
Alcohol 410 ccm 634 oz. 
Water 590 ccm OY oz. 


Bathe for 4 minutes, rinse in alcohol for 30 seconds, dry. 
Sensitises to 720, without any gap in the blue-green. 
Dicyanine may be used instead of the homocol with slightly 
greater speed. 

Greenfield's Bath—This bath is specially intended for 
tank work, but the solution should not be used more than 
twice : 

Pinachrome 3 ccm 23 min. 


28 PHOTOGRAPHIC FACTS AND FORMULAS 


Pinacyanol 2 ccm 15 min. 
Water 1000 ccm 16 oz. 
As all the isocyanines are decolourised by the carbonic acid 
dissolved in water, this bath would be rapidly decolourised, 
and in this state would not give such good results. A small 
addition of ammonia or borax 1s essential. In the above 
baths the dyes are used in 1: 1000 alcoholic stock solution. 
George's Formula.— 


Pinaverdol 13.75 ccm 105 min. 
Homocol 9 ccm 69 min. 
Pinacyanol 11.5 ccm 88 min. 
Ammonia 68.75 ccm 528 min. 
Alcohol, 90% 376 ccm 6 oz. 
Water to 1000 ccm 16 oz. 


This bath is too strong in ammonia. The dyes in the above 
bath should be used in a 1: 2000 alcoholic stock solution. 
Monpillard’s Formula.— 


Pinacyanol or dicyanine 5 ccm 38 min. 
Homocol 5 ccm 38 min. 
Ammonia 0.1 ccm 0.77 min. 
Water 1000 ccm 16 oz. 


With dicyanine the sensitiveness extends to 750, with pina- 
cyanol to 680. Stock dye solution 1: 1000 alcohol. 
DESENSITISING PLATES.—Luppo-Cramer found that by 
bathing plates in certain dye solutions both ordinary and 
colour-sensitive plates could be desensitised after exposure 
and thus be worked in a bright orange or yellow light without 
fog. Phenosafranine in a 0.05 per cent solution may be used 
with one minute’s bathing in the dark, or 10 per cent of a 
0.5 per cent solution may be added to the developer with 
equally good results. Other dyes of this class that act well 
are dimethylsafranine, amethyst violet, giroflé, safranine MN, 
phenosafranine and cresosafranine. Unfortunately, these 


ORTHOCHROMATIC PHOTOGRAPHY 4S) 


dyes are very tenaciously retained by the gelatine and can 
only be discharged by a nitrite bath, such as: 


Sodium nitrite lg 8 gr. 
Hydrochloric acid 10 ccm 80 min. 
Water 1000 ccm 16 oz. 


or a 2 per cent alum solution with an equal volume of hydro- 
chloric acid. The Hoechst dye works have introduced two 
new dyes for the same purpose, pinakryptol and pinakryptol 
green; the latter is the more soluble of the two and may be 
used as a preliminary bath or added to the developer, but 
the strength should be only 1:5000. Neither of these dyes 
stain the gelatine so much as the safranines. Lumiére and 
Seyewetz have found that aurantia in a 1: 1000 solution acts 
as a good desensitiser, and also toluylene red. This desensi- 
tising process is also applicable to screen-plates. 

ORTHOCHROMATIC FILTERS.—Yellow filters are used to 
cut down the excessive blue and violet sensitiveness of colour- 
sensitised plates. The quantity of dye given is calculated in 
grams of the dry dye per square meter, or grains per 1000 
square inches. It is advisable to dissolve the dyes in distilled 
water and add to the gelatine solution, previously prepared 
and filtered. 

To make the gelatine solution, immerse 125 g (614 gr.) 
soft gelatine in 500 ccm (8 oz.) distilled water, stir for 
5 minutes, and pour off the water. Again add the same 
quantity of water, allow the gelatine to soak for 10 minutes 
with an occasional stir, and pour off. Repeat the operation, 
allowing the gelatine to soak for 15 minutes, and pour off 
the water. Drain out as much water as possible, then melt 
the gelatine on a water bath in the water that it has absorbed. 
Add sufficient distilled water to make the total bulk 1000 ccm 
(16 oz.), and filter through glass wool or well-washed 
absorbent cotton. 


30 PHOTOGRAPHIC FACTS AND FORMULAS 


To make the dyed gelatine, the following quantities of 
filter yellow (Hoechst) should be used (Hubl) : 


No. 1. Filter yellow 0.5 g 4.97 gr. 
No. 2. Filter yellow 10g 9.94 gr. 
No. 3. Filter yellow 20¢g 19.88 gr. 
No. 4. Filter yellow 3.4¢ 33.8 gr. 
No. 5. Tartrazine | 3.0 g 29.84 gr. 


The above quantities of dye should be dissolved in 50 to 100 
ccm (384 to 768 min.) distilled water, and added to sufficient 
gelatine solution to make 700 ccm (15 oz., 435 min.) in all. 
This quantity should be coated on 1 qm or 1000 sq. in. of glass. 

The increase of exposure with these filters varies with the 
colour-sensitiveness of the plates used, but the following will 
be some guide: 

No. 1. Increase from ¥% to 2, according to plate. Can be 
used for instantaneous work and portraiture in the studio. 

No. 2. Increase from 2 to 6. Can be used for distant 
mountains and costume studies. Yellow reproduced the same 
tone as blue. 

No. 3. Increase from 6 to 8. Gives yellow much brighter 
than blue. 

No. 4. Increase from 4 to 12. Correct luminosity filter. 

No. 5. Increase from 4 to 15. Contrast filter. Reproduces 
blue like black, yellow like white. Suitable for cloud studies 
in which the sky is to be very dark, and furniture. 

Konig recommended the following quantities of filter 
yellow to the same areas as above: 


No. 1. Filter yellow 0.146 g 2.25: 8%) 
No. 2. Filter yellow 0.292 g 4.5 gr. 
No. 3. Filter yellow 0.594 ¢ 9.0 gr. 
No. 4. Filter yellow 1.167 g 18 gr. 


The increase in exposures should be 1.3, 1.7, 2, and 3 re- 
spectively. 


Plate Backing 


CARAMEL Bacxinc.—A non-actinic coating is applied to 
the back of glass plates to prevent halation, or the reflection 
of brightly lighted objects from the back surface of the glass. 
To be effective the backing must be in optical contact with 
the glass, and should theoretically be of the same refractive 
index. 

Caramel or burnt sugar does not dry, but a crystal caramel 
powder, which dries hard, is obtainable commercially. This 
can be made as follows: place some white sugar in a stewpan 
and heat over the gas, stirring continuously until it melts. 
The temperature will then rise very rapidly to 222° C. 
(430° F.). Continue heating for 15 minutes, stirring all the 
time; bubbles of gas will be given off and a clear red fluid 
formed, which gradually thickens. The heat should not be 
continued more than 5 minutes longer at this stage, or the 
product will be spoiled. Then pour out on a sheet of metal 
or slate, and it should set hard and brittle. Break up into 
small pieces, place in a wide-mouthed bottle, add water equal 
to one third the height of the fragments, and leave for three 
days. Add ten times the volume of wood or denatured alcohol 
or methylated spirit, and shake well two or three times in 24 
hours. Pour off the alcohol, which extracts the sticky part, 
and add sufficient water to the residue to make a fairly thick 
liquid. This dries hard but brittle. If one eighth of the 
original mixture, before the addition of the alcohol, be added, 
it loses its brittleness. Instead of dissolving in water, it may 
be poured out in a flat dish, allowed to dry, and then 
powdered. A suitable backing mixture is: 


31 


74 


Or: 


Mix and strain through muslin. 


PHOTOGRAPHIC FACTS AND FORMULAS 


Crystal caramel powder 500 g 
Gum arabic 250 g 
Water 750 ccm 
Caramel powder 500 g 
Water 250 g 
Denatured alcohol (methylated 

spirit ) 150 g 


502. 
24 oz. 
7 02. 


10 oz. 
5.0 


3 02. 


Ordinary caramel or the 


above may be mixed with a thick gum arabic solution and 


burnt sienna or lampblack in equal weights. 


ing may be used: 


Dextrine 50 g 
Crystal caramel 200 g 
Ammonium chloride 4.5¢ 
Water 200 ccm 
Alcohol 200 ccm 
Glycerine 25 ccm 


Work up into a stiff paste. 
ASPHALT Back1nG.—Dissolve powdered asphalt in ben- 
zole, chloroform or, preferably, carbon tetrachloride, to form 
a dark brown liquid. Apply with a brush. This dries very 
rapidly. 
Cornu’s BacKING.— 


Use enough lampblack to form a stiff paste. 
long time to dry and has a very ae smell. 
STAINED COLLODIONS.— 


Oil of cloves 6 parts 
Turpentine 7 parts 
Lampblack q.s. 


Aurine 45¢ 
Enamel collodion 1000 ccm 


Or the follow- 


V4 oz. 

1 oz. 

10 gr. 

1 oz. 

1 oz. 
60 min. 


This takes a 


35 gr. 
16 oz. 


POATE BACKING “75 


oh 
Nigrosine, spirit soluble 10 ¢ LAS 
Pyroxyline 30 g 250' er: 
Methyl alcohol 400 ccm 634 oz. 
Ether 600 ccm OY oz. 
Castor oil 60 ccm 460 min. 

Or: 
Celluloid scraps 45 ¢ 350 gr. 
Nigrosine 10 ¢g I Ee 
Amy] acetate 250 ccm 4 oz. 
_ Acetone 750 ccm 12 oz. 


This takes some hours to dry. By replacing the amyl acetate 
with methyl alcohol, a much quicker drying mixture is 
obtained. These, like the asphalt backings, are sometimes 
difficult to remove, but friction with soap and water readily 
removes them. 

Brack Bacxine.—For ordinary, non-colour-sensitive 
plates, the following may be used: 


Burnt sienna, paste 750 g 34 Ib. 
Dextrine 63 g Loz. 
Water 63 ccm az 
Phenol (carbolic acid) 5 ccm 50 drops 


For panchromatic plates, use ivory sienna black instead of 
the burnt sienna. These pigments can be obtained from any 
colourman, ground in water. Mix the dextrine and water, 
heat until dissolved, and then work in the colour paste and 
the carbolic acid, which is merely added to prevent the stock 
from growing mouldy. 
CHREVETOTS BACKING.— 

White castile soap 60 g 46 er. 

Alcohol, 90° 1000 ccm 16 oz. 
Dissolve in a water bath and add: 


34 PHOTOGRAPHIC FACTS AND FORMULAS 


Erythrosine 10g 77 gr. 
Aurine 8¢g 61 gr. 
Ivory black 8g 61 gr. 


This will dry in 10 minutes and can be readily removed with 
a. damp sponge. 
QUICK-DRYING SOAP BACKING.— 


Soap 45¢ 346 gr. 
Denatured alcohol (methylated 

spirit ) 1000 ccm 16 oz. 
Erythrosine 14¢ 107 er. 
Aurine 14¢ 107 er. 


Scrape the soap into fine powder or shavings, digest in the 
alcohol for a week with occasional shaking, add the dyes, 
and filter. 

BACKING SHEETS.—Black or red paper, gummed or coated 
with dextrine on one side, may be used, but is less efficient 
than any of the others. Sheets that can be repeatedly used 
may be made by coating cloth or paper with: 


Soft gelatine 1 part 
Water 2 parts 
Glycerine 1 part 


Soak the gelatine in the water and melt in a water bath; add 
the glycerine, then add lampblack, nigrosine, water soluble, 
or ared dyetocolour. Or printing-out paper may be exposed 
to light until dark, then washed, dried, soaked in glycerine, 
and squeegeed to the back of the plate. 

OxGALL (BoLas).— 


Oxgall, purified OL part 
Gum arabic mucilage 4 parts 
Red or black water colour 1 part 


The water colour should be obtained in a tube ground up in 
water. This should be applied with a stiff brush, and a sheet 
of black celluloid or paper applied. 


Focus and Optics 


To FInp THE FocaL LENGTH oF A LENS.—Many methods 
have been suggested for finding the focal length, equivalent 
focus, or focus of a lens, and many of them require a knowl- 
edge of the position of the nodal point of emergence. This 
can be found by calculation, but it can also be determined by 
temporarily mounting the lens in a V-shaped groove on a 
small block of wood, so that the lens can be moved to and fro. 
Or take a large flat cork and drive a nail through the center, 
so that the cork will turn on this as an axis. Fasten the lens 
to the cork by a rubber band, and focus some very distant 
object, such as the sun or moon, on a piece of card or ground 
glass also temporarily held on a cork. When the image is 
quite sharp, rotate the lens, and, if the image moves, the nodal 
point of emergence of the lens is not over the point of rota- 
tion of the cork. The lens should be shifted to and fro and 
the image again focussed until it no longer moves with the 
rotation of the lens. Then the node of emergence is exactly 
over the axis of rotation, and this is the point from which the 
focal length should be measured. 

The following method is accurate and calls for measure- 
ments which are easily made. Focus a foot rule to a definite 
size, measure the distance between the rule and the image, and 
call this D. Then focus to a larger size, again measure the 
distance as before, and call this d. Then the following 
formula will give the focus: 

d 


Ppt IPED iW 
r+l\ (R*+1 

( a ( R ) 

__R being the ratio of image to object in the first case, and r 


Sh 








36 PHOTOGRAPHIC FACTS AND FORMULAS 


that in the second case. Example: D = 62.7 in.; d = 72.2 in.; 
R = 4and r = 5; then 72.2 — 62.7 = 9.5; then (5 X 5+ 1) 
~—5=—26/5 and (4X4+1)+4=17/4; then 26/5 — 
17/4 = 19/20; and 9.5 + 19/20 = 10 in., the equivalent focus 
of the lens. 

Another Method.—This method can be carried out in any 
room. First focus on a very distant object, and mark the 
extension of the camera; then focus on a comparatively near 
object, that is to say, one in the length of an ordinary room, 
again mark the position of the camera, and call the distance 
between the two marks x. Again focus on a still nearer 
object, again measure the distance beyond the infinity mark, 
and call this distance y. Let B be the distance between the 
two objects, then the focus f= V~bry~+ y—-. Suppose 
the distance of one object is 144 in. and that of the other 
96 in., then B = 144— 96 — 48. And suppose the extension 
of the camera beyond the infinity or distant mark for - 
the object at 12 ft. was 1 in. and at 8 ft., 1% in., then 
f= V4X1X14=1%—1= V72=%=v14 =12. 
In this method, if the lens is moved in focussing, the distance 
between the object at the two positions, or B, must be ascer- 
tained by measuring from some part of the camera front. 
If, on the other hand, the focussing screen is moved and the 
lens remains stationary, we need only measure the distance 
between the two positions of the object. 

Another Method.—Set up a foot rule on a wall, and shift 
the camera until an image is obtained on the ground glass 
that is exactly the same size as the rule; naturally, how much 
of the rule is included depends on the size of the ground 
glass. Then measure the distance between the rule and the 
image, divide this by 4, and the result will be approximately 
the equivalent focus. } 

Or set up the foot rule as in the previous method, and 


PYCUSFAND OPTICS 37 


make the image not more than one-fourth of the size of the 
object ; then make a negative of the foot rule, and, calling the 
distance between the rule and sensitive plate D and the ratio 
of reduction r, which can be found by measuring the length 
of the image on the negative and dividing into the length of 
the foot rule, then f = D X r+ (r-+1)*. Example: a rule 
of 150mm was found to give an image of 13.4mm, D was 
800 mm, then r = 150 ~ 13.4 = 11.19; then f = 800 X 11.19 
— (11.19 + 1)* = 67.78 mm. 

Another Method.—Focus on a near object, then move the 
object further away from the lens by a distance D, refocus, 
note the distance through which the focussing screen has been 
moved, and call this a. Again move the object away from the 
lens another distance equal to the first distance D, and 
call the distance the focussing screen has moved Jb, then 
f=V2DXbXa(b+a) + (a—b). The lens must re- 
main stationary in this method. Let D=96,a=—2,b=—¥; 
eee ee 0 XK 2X 292 2) (2) = 
V 480 — 1.5 = 14.61. 

Another Method.—Reverse the lens in its flange, focus on 
infinity, or a very distant object, and call this distance b. 
Replace the lens in its ordinary position, and again focus on 
infinity. Now focus on a near object at a distance D, measure 
the extension of the camera beyond the infinity mark, and 
call this y; then f= V(D—b)y. Let D=48, b=8, 
y=; then f = V (48—8)% = 4.472. 

Pinhole Method.—The focus can also be found by means 
of a pinhole. Focus on infinity with the lens, and measure 
the size of the image or make a negative. Then place a 
pinhole in the position of the lens, and produce an image of 
the distant object exactly the same size; the distance of the 
pinhole from the image is the focus. A simple thin lens may 
be used instead of the pinhole. Or, if a lens of known focus 


38 PHOTOGRAPHIC FACTS AND FORMULAS 


is available, it is only necessary to measure the size of the two 
images, when both lenses are focussed on the same distant 
object, and the focal lengths are proportional to the sizes of 
the two images. 

A Geometrical Method.—Focus two distant objects, as A 
and B in Fig. 1, and let C and D be the images of these 


& 





Fig. 1 


objects; then f = h—~tan a, a being the angle between AC 
and BD. Measure the length h, the distance between the. 
images of the two objects, and also CL, their distance from 
the lens; then f =h~(CD—~CL). Let CD or h=4 in. 
and CL = 8 in.; then f = 4~(4~ 8) =8. 

Another Geometrical Method —At a distance a, at least 
100 times the focus, set off at right angles to the axis of the 
lens two marks % a distant from the axis. The distance 
between the two images on the screen will be 1% f. 

Grubb’s Method—At each side of the focussing screen 
make a pencil mark equidistant from the center. Place the 
camera flat on a sheet of white paper in front of a window. 
Focus on a very distant object, so that its image falls exactly 
on one pencil mark. Then draw a pencil line along the side 
of the camera, using the edge of the camera as a straight 
edge. Shift the camera so as to bring the image of the same 
object on to the other pencil mark on the ground glass, and 
again draw a line along the side of the camera, using the same 


FOCUS AND OPTICS 39 


side as before. Produce these two lines so that they meet 
in the point A, Fig. 2. Bisect the angle BAC by the line AD, 


PF c 


Fig. 2 


and draw a line EF at right angles to this line, equal to the 
separation of the pencil marks on the ground glass; the focal 
length is then AG. 

Smith's Method—T. Smith, of the National Physical 
Laboratory, London, has given another method of finding 
the equivalent focus of a lens, based on the focussing of the 
image of a distant object on the lens axis upon the ground 
glass of the camera, using first the complete lens and then 
each component separately. The optical rule that serves as a 
basis of the method is that the focus of a lens of focal length f 
is at a distance equal to fF ~ f’ from that of the combination 
of focal length F formed by placing in front of the first lens 
another of focal length f’. The method is carried out as 
follows: fit the complete lens to the camera, and focus sharply 
on a distant object. Mark the position of some part of the 
lens front or moving baseboard against a fixed part of the 
camera. Now remove the front combination, and again focus 
on the object, noting the distance d through which the lens 
front requires to be racked out; this distance is fF ~ f’ in 
which F is the focal length of the whole lens and f and f’ 
those of the combinations. Now focus again with the whole 


40 PHOTOGRAPHIC FACTS AND FORMULAS 


lens on the same object, the lens being placed with the back 
combination to the front. Mark the position as before, then 
refocus after removing the front combination, really the back 
one now in front. The distance d’ between the two positions 
is f/F +f. Hence dd’ = F’, that is to say, by multiplying 
the two distances d and d’ together and extracting the square 
root, we get the focal length. 

Lockett’'s Method—A. Lockett suggested the following 
method: First draw two short vertical lines at about the 
center of the focussing screen, exactly 1 inch apart and 
parallel with each other. Focus sharply on a far distant 
object, such as a remote church spire or factory chimney, 
and mark carefully om the camera baseboard the exact posi- 
tion of any convenient part of the moving lens front. This 
may be called the infinity mark. Now measure off 1 inch in 
advance of this mark, and rack out the camera until the same 
point of the front is against this l-inch mark. Fix up a 
foot rule at about the height of the lens, and move the whole 
camera to and fro, without any other adjustment, until the — 
rule is in the sharpest possible focus at full aperture, and 
with the commencement or zero of the graduations coinciding 
with one of the pencil lines. Then the number of inches of 
the rule seen on the ground glass between the two pencil lines 
will be equal to the focal length of the lens. This method is 
based on the following reasoning: let F be the equivalent 
focus, and r the ratio or proportion between the size of the 
image and the object. Then the minor conjugate focus, or 
the distance from lens to ground glass, is F + Fr. When 
the camera front is set 1 inch from the infinity mark, then 
F —~~r equals 1 inch and must also be equal to F — F; there- 
fore r equals F. It is not essential to adhere to the 1-inch 
extension, and a greater distance will eliminate errors in 


POCUS AND OPTICS 41 


measurement, but the distance between the marks on the 
ground glass must always be the same as the extension of 
the camera from the infinity mark. 

DeptH oF Focus ScaLe.—Decide what stops the scale is 
to be constructed for. As a rule, it will be found sufficient 
to calculate for f: 8, f: 16, f:24, etc., as with larger apertures 
the scale becomes too confused, and one rarely uses a larger 
aperture than f:8 for snapshot work. Draw a scale each 
division of which is equal to one-hundredth of the aperture, 
this being the assumed diameter of the circle of confusion; 
if this degree of sharpness is not considered sufficient, one 
may adopt one-two-hundredth or smaller, but, obviously, the 
smaller the divisions the more confused the scale and the less 
value practically. Besides that, one cannot estimate the dis- 
tance of an object with sufficient accuracy for the smaller 
scales. Utilising the formula 100 X focus squared ~ ratio 
aperture (100 F* —~~r), find the nearest points in focus. 
Mark off on the divided scale these distances, starting from 
the infinity point, as in Fig. 3. 


cw 38 191 % 6 4 3% 
Fig. 3 
Construct another scale of like dimensions and divisions, and 


mark off with the stop apertures only, starting in the center 
as in Fig. 4. 


¥64 F320 F16 F8 FS Fl6 = -F32 F64 
Fig. 4 

By placing Fig. 4 over Fig. 3 and sliding it along so that the 

arrow in the center marks the distance focussed on, one can 

at once read off under the stop numbers the distances which 


42 PHOTOGRAPHIC FACTS AND FORMULAS 


will appear sharp in front of and behind the object focussed 
for. The following table shows the distances for a 6-inch 
lens starting with f:8, though in the scales only the nearest 
whole numbers are given: 

100 & 6* + f:8 = 450 in. = 37 ft. 6 in. 

100 X.6* + f: 16 == 225 in. = 19 179i, 

100 & 6? + f:24 = 150 in. = 12 ft. 6 in. 

100 & 6* + f:32 =112Y in. = 9 ft. 4Y in. 

100 & 6° + f:40 = 90 in. = 7 ft. 6 in. 

FocussING SCALE.—To construct a focussing scale, draw a 
line equal in length to the equivalent focus of the lens, mark 
off exactly the half, third, fourth, sixth, eighth, etc., and add 
1 to each division; this will give a scale as below. Multiply 
the numbers below the line by the focus of the lens, and the 
result will be the distances in inches at which an object will 
be sharp, if the lens be placed at this point. To fix this scale 
to a camera, focus first on the clouds, or a very distant object, 
mark the baseboard at any convenient part of the camera 
front, and place B even with this mark, the scale extending, 
obviously, from this mark away from the rear of the camera. 


3 4 5 79138 
Fig. 5 


DreptH oF Focus.—Welborne Piper suggests that, know- 
ing the hyperfocal distance for the stop in use and the 
distance of the object in sharp focus, if we divide the product 
of these two distances by their sum, the result will be the 
distance of the nearest object in focus; if their product is 
divided by their difference, the result is the distance of the 
farthest object in focus. Example: suppose we are focussing 
with a 6-inch lens on an object 10 ft. away, taking 1/100 in. 
as the circle of confusion. The depth constant for the lens is 


HOCUS ANDVOPRTICS 43 


100 >> 6° = 3600 in.=- 300 ft. The hyperfocal distance, 
which is always equal to the focal length multiplied by the 
diameter of the aperture, and divided by that of the circle of 
confusion, is therefore for a 6-inch lens at f:6, 300-6 or 
50 ft. When focussing on 10 ft., the near depth is (50 & 10) 
+ (50+ 10) =81/3 ft. The limit of far depth is (50 X 
10) + (50 — 10) = 12¥Y ft. When focussing on infinity, the 
nearest object in focus is at the hyperfocal distance, and depth 
extends from that point to infinity. When the hyperfocal 
distance is focussed on, the nearest object in focus is at half 
the hyperfocal distance, and the farthest at infinity, so that 
depth extends from half the hyperfocal distance to infinity. 

Focussinc Rutes ror Hanp CAmeErAs.—The following 
two simple rules may be useful to hand camera workers. 
1. Applicable when the background is not very distant: Focus 
on a distance equal to twice the product of the greatest and 
shortest distances, divided by their sum. Example: Suppose 
the subject to be a street scene with a house 20 yards away, a 
man 5 yards away, and both are required to be sharp; then 
(20 x 5) + (5+ 20) X¥ 2=8 yards. 2. Applicable when 
the background is infinity or very distant: Focus on a point 
just double the distance of the nearest point. Example: 
again suppose that the nearest point is 5 yards distant; then 
the point to focus on is 5 &X 2 = 10 yards. 

The following rule may also be used: square the focal 
length of the lens in inches, multiply by 100, divide by the f 
number of the diaphragm, and then divide by 2. Example: 
With a lens of 5 in. focus at {:8; 5X5 & 100 = 2500; 
2500 ~ 8 = 312%, and 312%4 —2 = 156 in. Then every- 
thing beyond 156 in. (13 ft.) will be in focus if this plane 
be focussed on. 

ComBINING LENsES.—To find the focal length of two 
lenses separated by a short distance, multiply the focal lengths 


44 PHOTOGRAPHIC FACTS AND FORMULAS 


together, and divide by their sum less the distance of separa- 
tion. Let f’ and f’’ be the foci and d the separation of the 
two lenses; then the final focal length will be (f’ & f”) ~ 
(f’ + f’’—d). Example: a 6-inch and an 8-inch lens are 
to be combined with a distance of separation of 1 inch; the 
focus will be (6 X 8) + (6+ 8—1) =48~— 13=3¥Y. To 
find the focal length of a supplementary lens or magnifier to 
reduce or increase the focal length of a given lens, multiply 
the focal length F to be altered by the final focal length 
desired, and divide the product by the original focal length 
less the final focus. Example: it is desired to reduce the 
focal length of a 10-inch lens to 7 inches, then 10 * 7 = 70, 
10—7 =3, and 70~3=231/3. To reduce the focal 
length, positive or convex lenses must be used; to increase 
the focus, negative or concave lenses must be used; and, in 
this case, the focus of the lens to be added is prefixed by the 
minus sign in the formula. Example: to lengthen a 7-inch 
lens to 10 inches, 7 X 1070, and 7— (+10) =—3, 
therefore 70 ——3 = —23 1/3. A very simple rule to re- 
member as to the focus of a magnifier for reducing the focus, 
or, in other words, to take near objects close to the camera, 
is that the focus of the supplementary lens must be equal to 
the distance of the object. In this calculation the separation 
of the lenses has been neglected; to take this into considera- 
tion is a refinement that merely complicates calculations. 
Ratio APERTURE OF DIAPHRAGMS.—The ratio or effective 
aperture of the stops or diaphragms does not coincide with 
their actual diameters in consequence of the condensation of 
the light by the front lens component in compound lenses. 
To determine the correct ratio aperture, focus the lens for 
parallel rays, that is, for a very distant object; then replace 
the focussing screen with an opaque card, in the center of 
which is a pinhole. In a dark room place a light behind the 


FOCUS AND OPTICS 45 


pinhole, and a circle of light will be found on the front glass 
of the lens; the diameter of this circle will be the true aper- 
ture of the stop, and dividing the focal length by this gives 
the true ratio aperture. As it is sometimes difficult to see the 
circle of light on the glass, the latter may be dusted with talc, 
which makes it more readily visible. Or a small piece of 
bromide paper may be cut and placed inside the cap of the 
lens, and a fairly long exposure given to the light passing 
through the pinhole and the lens. On development the 
diameter of the black circle is the diameter of the ratio 
aperture. Another method is to focus a bright spot of light 
at infinity or a great distance, and then move the focussing 
screen until the spot of light becomes a disk of any definite 
diameter, say, half an inch. Then the distance the focussing 
* screen was moved divided by the diameter of the disk of light 
is the diameter of the ratio aperture. To find the diameter 
of the stops for a lens, the following approximate method 
may be adopted: Find the equivalent focus F of the lens, 
measure the distance between the two outer surfaces of the 
front and back lens, call this d; then the diameter of the stop 
f:x will be (F— Y%d) ++. Example: focus of lens, 16 
inches, distance between the surfaces or d, 2 inches; if the 
desired stop is f:8, then 16—(% XK 2) +8=16—1—8 
= 1% inches, the diameter for f:8. 

Piper’s TABLE OF ANGLES OF VIEW.—To find the angle 
included on any given plate, divide the diagonal of the plate 
by the equivalent focus of the lens. The quotient T is equal 
to twice the tangent of half the angle, but the value of the 
angle can be found very nearly from the following table: 


If T is The angle If Tis The angle 
less than is less than less than is less than 
0.3 be ie/, Si1° 


0.35 20° es : 1.8 84° 


46 PHOTOGRAPHIC FACTS AND FORMULAS 


74s The angle If T is The angle 
less than is less than less than is less than 
0.4 Oe 1.9 87° 
0.45 254° 2.0 90° 
0.5 28° Zit 03% 
0.55 Sit Le 9514° 
0.6 3314° 253 98° 
0.65 36° 2.4 100%4° 
0.7 39° Vspes 103° 
O75 414° 2.6 105° 
0.8 44° Pant 10 fe 
0.85 4614° 2.8 109° 
0.9 48° 2.9 Vits 
0.95 Behe 3.0 11214° 
1.0 Son 3:2 116° 
‘hat 58° 3.4 119° 
12 62° eee iZ2- 
1.3 66° 3.8 1241%4° 
1.4 70° 4.0 1272 
ie, 74° 4.3 130° 
1.6 isa 4.7 134° 


To determine the covering angle, the diameter is taken as 
equal to twice the distance from the principal axis of the lens 
to the farthest corner of the plate. To determine the view 
angle, we take simply the diagonal of the plate as the diameter. 
The diagonals of ordinary plates and films are: 


24%x34....40in. 5. 7 aa 
24%4x4%....4.9 in. 5. x74 .. o ee 
34%x3%....4.6 in. 6%x 8Y....10.7 in. 
34, x4%....5.3 in, 8 x10: Cea 
3144 x5....64 in. 10. x 12 fae ee ee 
Alsen 2 GMO ues 16:. x ZO ee ee 


434 x6%....8.0 in. 20. X Z40C CC Lae 


HOGS ANDIOPTICS 47 


CoRRECTION FoR NON-ACHROMATIC (SPECTACLE) LENSES. 
—After focussing, the distance between the lens and plate 
must be decreased by approximately 1/40 the focal length of 
the lens, in the normal use of the lens when photographing 
distant objects. In portraiture, copying, etc., the correction is 
greater, as follows: 

Ratio of reduction Infin. 1/10 1/5 3/10 4/10 % 6/10 7/10 4/5 same 
Correction (% of nae 
focal length) Oe 2) 9.4 62,6 98 18) 82". 8.4) 3.6 4 

TELEPHOTO ForMuLAS.—Let M be the magnification, 1. e., 
the number of times the image produced by the complete 
lens is larger than that produced by the positive lens alone; 
F the focal length of the complete lens; f’ the focal length of 
the positive lens; f’’ the focal length of the negative lens; 
E the camera extension from negative lens to plate. To find 
the magnification M: Divide the camera extension by the 
focal length of the negative lens, and add 1, or M = (E ~ 
f’’) +1. To find the camera extension: Multiply the focal 
length of the negative lens by the magnification minus 1, or 
FE =f’’ (M—1). The focal length of the whole lens for 
distant objects equals the focal length of the positive lens 
multiplied by the magnification, or F = Mf’. For near ob- 
jects when reducing N times, F = (mE + f’) + (mN +1), 
im which m=the ratio of f’ to f”, i. ec, f’ +f” (Dall- 
meyer ). 

Assume the same notation as above. The separation of the 
positive from the negative lens = (f’ —f”) + (f”=+M). 
Example: Suppose the positive lens has a focus of 7 in., the 
negative a focus of 3 in., what separation will be required for 
4 magnifications? Ans.—(7—3) + (3~+4) =4%. An 
alternative formula giving the separation necessary to obtain 
a telephoto combination of a desired focal length is (f’ — 
f’) +f’ Gf” =F). Example: suppose the positive lens is 
9 in. focus and the negative 4 in., what separation is required 


48 PHOTOGRAPHIC FACTS AND FORMULAS 


to make the combined focus 16 in? Ans—(9—4) +9 x 
(4+16)=5+9X 4%=—5+24%=—7% in. Where a 
scale of magnification is marked, as on the ordinary type of 
adjustable mount, and another magnification is desired that 
is not marked, let M’ stand for any existing marked magnifi- 
cation, M” the magnification desired. Then f” k (M’ — 
M’”) -— (M’ X M”) will be the increase of separation re- 
quired. Example: Suppose a magnification of 5 be wanted, 
and the nearest mark is 3, the focus of the negative lens 
being 414. Then 4% X (5—3) + (5 X 3) =4% X 2/15 
— 3/5 in., which is the necessary extra separation readily 
measured from the existing mark for 3 magnifications. When 
the focus of the negative lens is not known, it is easy to find 
it from the distance between any two magnification marks on 
the mount. The rule is: multiply the two magnifications 
together and divide by their difference, multiplying the quo- 
tient by the distance D between the two marks; (M’ XK M”) 
— (M’—M”) XD. Example: suppose the distance be- 
tween the marks 8 and 4 on a telephoto mount is 3% in., then 
(8 X 4) + (8—4) XK % = 32/4 X % = 6 in., which is the 
required focus (Lockett). 

PINHOLE Exposure.—The correct exposure is, with the 
small pinholes used in practice, always greater than that cal- 
culated on a basis of relative aperture ratios. The inverse 
square law cannot be applied in calculating relative exposures 
at varying plate distances from one and the same pinhole. 
Using a pinhole made with a No. 12 needle, the pinhole 
exposure factor by which the aperture ratio numbers must 
be multiplied varies from 1.6 to 1.42 as the plate distance 
diminishes from 254 to 128mm (Carnegie). 

Watkins finds that it is better to expose with a pinhole for 
50 per cent longer than the exposure calculated on the ratio 
aperture, and gives the following table based on 1/40 instead 


Hocus AND OPRTICS 49 


of 1/60 inch, the numbers being called Watkins-Power, or 
W.P. Nos. 


Nearest Nearest 


Decimals vulgar needle Working 
W.P.Nos. ofinch fractions size distance 
1 .160 Vie ey tp ee 
Z 080 1/13 Le A Ae pale 
3 053 1/19 1 40 in 
4 .040 P25 4 20 in 
5 032 1/31 5 14 in 
6 027 1/38 7 10 in 
7 023 1/44 8 8 in. 
8 020 1/52 10 Sin 


Multiply the W. P. No. of the aperture by the working 
distance from the plate. Use the result as the f number with 
which to calculate the exposure by table or meter. Whatever 
the calculated result is in seconds or fractions of a second, 
expose that same number of minutes or fractions of a minute. 

To find the best diameter of pinhole for a given extension 
of camera: divide the square root of the extension by 120. 
Example: extension = 11 in., square root of 11 = 3.316, and 
this divided by 120 = 0.0276 in. or approximately 1/36 in. 

To find the extension of camera for a given size hole, 
multiply the diameter of the hole by 120, and square the 
result. Example: diameter = 1/40, then 1/40 < 120 = 3, 
and 3 X 3 =9 in. 

ConjJUGATE Foct.—The relative distances between the neg- 
ative and lens, and lens and image, for enlarging and reduc- 
ing, that is, copying in the camera or making lantern slides, 
can be found by the following simple rule: divide the longer 
side of the enlargement desired by the longer side of the 
negative, and the result will be the “times” of enlargement ; 
it should be noted that this is linear and not area enlargement. 


50 PHOTOGRAPHIC FACTS AND FORMULAS 


Then multiply the focus of the lens by the times of enlarge- 
ment plus 1, and the result will be the distance between lens 
and sensitive surface. This distance divided by the times of 
enlargement will give the distance between the lens and nega- 
tive. Example: to find the distances for enlarging a 4x5 
negative to 16 x 20, the times of enlargement = 20 — 5 = 4. 
Using a 6% in. focus lens, 6% & (4+ 1) =32Y and 32% 
48% in. The greater distance is called the major con- 
jugate focus and the lesser the minor conjugate. In reducing 
or copying, these distances are reversed, that is, the major 
conjugate or greater distance is between the subject and the 
lens and the minor between the lens and the sensitive surface. 

How to Care For Hico Grape Lenses.—The lens should 
be capped when it is not in use. Avoid sudden and extreme 
temperature changes. The lens should not be exposed to 
acid fumes. Avoid placing or leaving lens where dampness 
or moisture may collect on it. Do not permit lens to fall, or 
subject it to a sudden jar. Occasional cleaning is not only 
advisable but necessary when dust, finger marks or moisture 
show on the lens surfaces. For this a camel’s hair brush and | 
a clean, soft, linen cloth are desirable. Proceed as follows: 
Remove dust with camel’s hair brush. Breathe on lens 
surface, and with cloth wipe lightly with a circular move- 
ment. If finger or dust marks cannot be removed, rub the 
surface gently witha tuft of cotton moistened with clean warm 
water. Dry the surface with a piece of clean linen cloth. 
Under no circumstances use abrasives or any kind of polish- 
ing or cleaning material. Never use acids, alcohol, alcoholine 
or other solvents on the lens surfaces or on the mount. Only 
in extreme cases should lens elements be removed from their 
metal mounts to clean inner surfaces. When replacing same, 
see that they fit evenly and firmly in the mount. 


Exposure 


TIMING SHUTTER SPEEDS.—Using a pendulum for this 


purpose, the speed of the bob is in feet per second 


ex gl ( sin’ — sin? 


in which g = force of gravity at the place of experiment, 
32.2 being sufficiently approximate, /] = length of pendulum 
in feet, B the angular displacement from vertical of bob at its 
highest position, C the angular displacement from vertical of 
bob for position at which speed is required. From this a 
table can be calculated of the speeds of the bob over each 
5 degrees of arc and also the total period of the pendulum 
(Collingridge). 

THE AMERICAN PHOTOGRAPHY EXPOSURE-TABLES.*— 
Find numbers for subject, stop, light, month and hour, and 
plate. Add them, refer to table (page 60), and give exposure 
indicated. When the exposure fails to correspond with speed 
marking on shutter, use the nearest shutter speed, preferably 
the lower. 


Subject.— 
MM OT CLOUIS fy iy cee ee ee tee eens y 
Sea views, snow scenes, distant landscape ............ 1 
Open landscape with unimportant foreground ......... 2 
eeveraee landscape with forecround .............5.0¢- 3 
Landscape with dark foreground, groups in sunlight .... 4 
Merecteccenes, DUIdINOS, STOUPS........ 2. .ceeccsscees * 
Lp EGS a aa a a 7 
NS FAC ee a, gc a soi v's eo alg aiels od 8 to 10 
aa ae ee ee ae 8 to 16 





* Copyright, 1906, by F. Dundas Todd. Copyright, 1911, 1913, 1914, by 
F. R. Fraprie. Oopyright, 1912, 1915, 1916, by American Photographic 
Publishing Co. 


= 


52 PHOTOGRAPHIC FACTS AND FORMUEAS 


Stop.— 
23 2.89 | 3.394 | 49 | 4.792 
vs02s! |oasl! ose o7 4 19 | 14 


19 | 238 | 167 | 28 649 | 00 Ee 256 





Arey 


Light.— 
Intense sunlight (inky-black shadows) .............. 0 
Bright sunlight (strong shadows) ...............--. Y 
Faint shadow cast by. sun .......... cso 1 
Dull. (no shadows) ... 0.05.4... «0 05) sien 1% 
Very dull (whole sky very dark) ...... late Pe 


If sunlight falls over one shoulder, add 0; if straight across 
subject, add 1; if sun is ahead, add 2. When using back 
combination only of R. R. or symmetrical lens, add 2, unless 
actual f value of stop is known and used. 

Light VALUES FoR Various LATITUDES.—The following 
tables show the value of the light for each hour of the day 
and month for various latitudes and are calculated for use 
with the American Photography Exposure Tables. 

For 60° N.; Southern Siberia, Southern Alaska, Northern 
Canada, Iceland, Norway, Sweden, and Northern Russia. 


wor May Apr. Mar. Feb. Jan. 
M M June July Aug. Sept.” Oct, Way wee 
12 0 0 iY ol 1% 2 3 

Lboseas} 0 yeaa | 4 3 5 
LOGh ia y y% 1 1% 2 4 6 

OSS ait L422 3 5 

Is 1 1% 2 3 Mi 

FEED 1% 2 3 5 

Oe 2 3 5 

mh os 3 5 

4 8 5 


Dec. Nov. Oct. Sept. Aug. July June 
Jan. Feb. Mar. Apr. May 


EXPOSURE 


ie 


The months for latitudes north of the equator are given at the 
top of the tables, while those for the southern hemisphere are 


below. 


For 53° N.; British Isles, Northern Germany, Southern 
Canada, and Southern Russia. 


ee 
M M 
12 

1 es | 
eZ 
oo 
8 4 
Jann) 
So 5 
Te TH 
a 8 


June 
0 


May 
July 


0 


Jan. 


Apr. Mar; 
Aug. Sept. 
yY% 1 
yy 1 
Vols 
1 Z 
14% 2Y% 
zZ I 2 5 
5 
Octes Sept: 
Feb. Mar. 


Feb. 
Oct. 


ly 
2 
2Y2 
3 


5 


Aug 


Apr. 


Jan. 
Nov. Dec. 
2 4 
3 4 
4 5 
5 7, 
= uly ejine 
May 


For 40° N.; Northern United States, Armenia, Spain, 
Italy, Turkey, Japan, Greece, Pekin, and Central China. 


Noa ie 
MM 
12 
Pies) 
102— 2 
Oi 
8 4 
7S hae 
aen.6 
magne 7 


June 


May 
July 


Apr. Mar. 
Aug. Sept. 
0 Ve 
0 V2 

ee Ge, 
oa hak 
1 2 
4) 4 
4 
Oct. Sept 
Feb. Mar 


Feb. 
Oct 


Y 
VY, 


awn ®t) — — 


Jan. 
Nov. Dec. 
1 1 
1 1 
1y% 1Y% 
2 2 
53 4 
5 5 
Se tiuly a) une 
May 


54 PHOTOGRAPHIC FACTS AND FORMULAS 


For 30° N.; Southern China, Southern United States, 
Northern Mexico, Northern Africa, Arabia, and Northern 
India. 


Ahr: May. Apr. Mar. ©Febs jan: 
M M June July Aug. Sept. Oct. Nov, see: 
es yY% 0 0 0 0 yY% 1 
Para es 0 0 0 0 0 Ye ll 
Ce ae 0 0 0 0 ae: 1 
Bolg 0 0 yy yY% 1 1% 2 
8 4 yY% 1 14 ee 24% 3 
Asien 1% 2 22 195 4 5 
SPANK) “ 4 6 


Dec. Nov. Oct. Sept. Aug. July June 
Jan. Feb... Mar.” aiprse stay 
For 30° S.; Southern Australia, Northern Argentina, Cape 
Colony, and Uruguay. 


For 23° N.; India, Mexico, Southern Egypt, Central 
Arabia, Cuba, and Northern West Indies. 
aN a Bs May Apr. Mar. Feb. Jan. 
M M June July Aug. Sept. Och eveere, 
1 iy y y% 0 0 0 


1 0. 0 a rr % 

10:3 2.05.0) SOU ee Oe me i eae 
Sis Yas Cie Nae ee 1 1 ly 
PR REAR 1 1 14 We 2 
7 5 2 2 2 3) 55sas 
6b 8 Os 


Dec. Nov. Oct. Sept. Augei july ejaae 
Jan. Feb. . Mar. (Ape 
For 23° S.; Northern Australia, Northern Chile, Bolivia, 
Madagascar, RG Janeiro, and Transvaal. 


EXPOSURE 


55 


Tropics, 20° N. to 20° S.; Northern Brazil, Canal Zone, 
Central Africa, Ceylon, Borneo, Sumatra and Pacific Islands. 


tee af May Apr. Mar. Feb. Jan. 
nM ico uy re wAure sept.” Octh- Novo) Ded, 
12 0 0 —Yy% —-y% —% 0 0 
ea | 0 0 0 0 0 0 0 
Be 72 0 0 0 0 0 0 0 
ee t PR ie VERN a EARL BE A oPk Slo 
8 4 1% 1 1 i 1 1 ly 
i. a 3 PG 2a 24 lS 3 


PLATE SPEEDS.—The numbers in the first column indicate 
the exposure factors for use with the American Photography 
Exposure Tables. The letters in the last column are develop- 


ment speeds for Thermo Development. 


The other columns 


contain factors for use with the Burroughs-Wellcome, Wat- 
kins, Wynne and Harvey exposure meters. 


Amer. 

Phot. B.W. 
MER AG TU en ee cece ewes Sm ah oe 1/6 
PELE ACOLOF DIGG. ss csdies «0 0 e400: 
Ansco Speedex film ............. % % 
iar. mi. Ultra’ speed). ......... Ye 1/12 
ee INO SKTENG sass cece 4 1/6 
AYP. M: special rapid .......... 1 1/6 
PAMMEET EMG PTULTIN ot claret ¥ ci olaiisisie a oe see 1 % 
me tawerds HKnsign <2... .cescees 1 1/6 
A. Edwards Ensign speedy ...... 34 W% 
Mariet Ordinary ... 00s 0s.65.. Gas ee oP) 
Barnet Special rapid ............ 1% Yu 
OnE ia) a 1 1/6 
Pareet Hed Seal . os cee ce wses %4 1% 
Barnet Studio 400 ........... Sate te ¥% 
Barnet Studio 500 & Press ...... W% 1/12 
Barnet Ult. rap. & SS ortho ...... % .1/16 
Barnet Studio 400 ortho ........ 34 % 
eae ORGN cots 6 5 clciss.d so wie's 6 5's mm 1/12 
Breer Oh eA Doses ccle ene s % 1/12 
oo EES os Jit Si Wa 6 ae %4 % 
OE SES Slee WS 5 a 1% 1/3 
eamenen in PAL A ccc ence oe ole 3 1 
Serine TO! Rim oe Se eee 1 % 
Central Colornon ........ Dias aed | a 1 
Central Pan. Ortho. Com ........ 4 % 
(entval Comet §.....0.06605 hie Pee 1/3 
Dentral Special ....:-..cesee0. Ah ve! 1/6 


Central Special XX ...cccvsesee | I 


Wat. Wynne Har. Tay: 


130 73 #&E M 
250 100 D MS 
350 120 M 
250 100 M 
180 87 M 
180 87 M 
180 87 Ss 
250 100 Ss 

65 52 M 
130 73 MS 
180 87 M 
250 100 MS 
250 100 D M 
$50 120 D Ss 
500 143 &E Ss 
250 100 E M 
350 120 VS 
350 120 Ss 
250 100 Ss 
130 73 MS 

65 52 MS 
180 86 vs 

65 52) kd MQ 

65 52 #H MQ 
130 73 kG M 
180 86 E VS 
250 100 D vs 


56 PHOTOGRAPHIC FACTS AND FORMULAS 


Amer. 

Phot. B.W. Wat. Wynne Har. T.D. 
Central Wxcelal 73... 6. eases ee es % 1/12 850 1202299 Ss 
Oramere.COntrastiec crates sient’. ore 9 3 32 35 M VVQ 
Cramers Slow (leon: -si cles sic ' 5 1% 130 73 K MQ 
Cramer Com. & Com. Iso ....... . 1% Wy 130 73: 2H MQ 
Cramer Spectrum & Trichrome ... 2 1/3 90 60 H MQ 
Cramer Anchor & med. Iso. ...... 2 1/3 90 60 GH MQ 
Oramer. Banner X55 6. ven pines 1% 1/6 130 fen Ss 
Cramer Inst. Iso & Iso. Port. .... il 1/6 180 86 E MQ 
Cramer Crown. Post ..........- 1 1/6 180 86 E Ss 
Cramer Speed-o-krome .......... 1 1/6 1180 86 E Ss 
Oramer Hi-Speed. o..s6 ssise cc's 6 ne Wy 250 100 OD Ss 
Criterion Process ....... aitetote ote 12 3 32 35 M Q 
Criterion Ordinary ....... Nis ey 4 % 65 52 H Q 
Oriterion Iso ordinary .......... 2 1/3 90 60 H M 
Criterion Extra rapid ........... 2 1/3 90 60 iH MS 
Criterion Extra rapid Iso ........ 1% 4 130 yp oom * M 
Oriterion ‘Roll Alm: Gi. ws wea ois ewe 1 1/6 180 87 VS 
Criterion Cine film ..... ap RS gas 1% % 130 72 MQ 
Criterion Special Extra Rap. .... 1 1/6 180 87 VS 
Criterion Portreitic. tc eisie cocks wore 1 1/6 180 87 MS 
Criterion Enelite .......... secs. > \L/T2 > OS nOre ee vs 
Eastman Process film .......... 9 3 32 35 L MQ 
Eastman Cine Pos. film ......... 9 3 32 35 MQ 
Eastman Rapid plate ......-.... 1% Mu 130 72 MS 
Eastman Extra rapid plate ...... 1 1/6 180 87 MS 
Eastman Spl. ultra rapid ....... la % 180 87 MS 
Pasta ortho tise siccotmare eer ore 1 y 180 87 MS 
Kastman Super-sensitive plate ... % 1/12 350 120 vs 
Eastman Par-speed Port. Film ... % i, 250 100 D MS 
Eastman Cine neg. ord. ......... 1 1/6 180 87 S 
Eastman Cine neg. sup. speed .... % % 250 £100 VS 
Eastman Cine neg. pan. ..... os ee iB 130 72 MS 
Eastman Sup. Speed Port film .... % 1/12 350 120s vs 
Eastman Commercial ........... 2) at 2/3 65 bo tad M 
Eastman Commercial ortho ...... 1 % 180 oly ene tS MQ 
Gem'Processa) Pos oes ce ete tes : 5 1% 65 52 M Q 
Gem Universal Slow ............ 4 1 32 35 M MQ 
Gem Universal 2ts 5.6 45 wee 4 % 65 52° 7 M 
Gem Medinm >is saint eee 2 % 90 60 H S 
Gem (Tricol oo fase ee ee ee 1% % 130 87 Q 
Gem Ultra rap. studio .......... 1 1/6 180 St FF Ss 
Gem Noskrene & Sp. Rap. ....... 1 1/6 180 ST ar s 
(Form “Meteor. cscs ce bine pscietenaie es 1 1/6 180 BY oF M 
Stem , Lee: Says wise sy eden ere 1 1/6 180 87 =F M 
(Jem \ oll Him ns oc cir dt Ries 1 1 180 87 vs 
Gem portrait & Salon Iso ....... Oe Pee 1% 250 ST 28 Ss 
Gem Gold: label’ fos ini eae eee % 1/12 350" 3120 s 
Gem Salon XX & Iso .......... . MM  1/16> 5007 ise vs 
Gem Salon Film ...... ie iad aie 4 % 250 87 s 
Gevaert Ortho Process .......... 9 2 32 35 M M 
Gevaert Ordinary ......... : 4 2/3 65 52 I MQ 
Gevaert Ortho antihalo ......... 1 4, «180 87 E MQ 
Gevaert Filtered ortho .......... 1% u% 130 12 © MS 
Gevaert Spec. rapid ........ oe 1 1/6 180 8T iF MQ 
Gevaert Orthochrome ........... 1 1/6 180 BT oe MQ 
Gevaert Special sensitive ........ 4 44 260 T007) DB vs 


EXPOSURE 57 


Amer. 

Phot. B.W. Wat. Wynne Har. TD: 
Gevaert Sensima ..........- Rie ests L/len 20007 143) Ss 
Gevaert Sensima ortho .......... % 1flg 500 148 #E M 
Gevacrie@ine flim 200.5 0...20 0 2 1% 90 60 MQ 
Goerz Tenax Ultra rap ......... - & 1% 250 100 VS 
Goerz Tenax Ultra Iso ........ oe & 1% 250 100 Ss 
Goerz Tenax Hx. rap. ....... cee Oh 1% 250 100 MS 
Goerz Tenax Ex. rap. Iso ........ 1% % 130 72 MS 
Goerz Tenax Ex. Iso antihalo .... 1% yy 130 72 M 
Goerz Tenax film ..... ores BORO 1% % 130 72 MS 
Graflex roll film ............... 1 1/6 180 87 vs 
Griffin Com. & Prof. 125 ........ 2 1/3 90 60 M 
Griffin Com. & Prof. 250 ........ i 1/6 180 87 MS 
Griffin Com. & Prof. 375 ........ % 1% 250 100 VS 
orimine self ortho <......... Miereke 1 1/6 180 87 MS 
Griffin Gramme ........-.cesee- 1 1/6 180 87 MS 
Ratt ee COLL AIT 9.0 ches) ol 2 ss oe» 1 1 180 87 MS 
Mem T OBS iis) sires cc's «00,610 0. 6 ole 34 % 250 100 VS 
PUEITITN OF MOON iets se crs is 6's oye cee 6 0-6 4 1 65 52 Ar VQ 
Hammer Slow ortho ........++-- 14% 1 130 72 J VQ 
RIRINIMET LAST oe sis. c 1 se 00 ae See LG 1 120 70 MQ 
Hammer Ortho non-hal. ......... 1% 1 120 70 M 
Hammer Ortho extra fast ...... - 1% % 130 72 D M 
Hammer Aurora extra fast ...... 1% % 130 (ee E MS 
Hammer Postal & extra fast .... 1 1/6 180 87 E M 
Hammer Special extra fast ..... . %& 1% 250 100 D MS 
Hauff ortho anti-hal ........ aisesu eel i 1/3 120 70 M 
Pater LAVATIG Wis + so + 0 aiehatel el «ysis Y% 130 72 M 
Prauth xt. TAP. OTtHO ....2.c00e 1% 1/6 130 72 MS 
ER AUMUNELANTEADIG! cc clsrccle + occs se y% 1/12 350 120 vs 
HitOTOs PTOCOSSA. «oss s ces oc ehatehisnacs 9 2 32 3D M Q 
Miiordsmap. TOC, Pan... <<... 1% 2 1/3 90 73 VVQ 
PifOrd. Half-tOnG «2.66... 2s soon CRA ul 65 52 aL Q 
TOCOsOTOIMALY ine sis os cls 6 he anes mene 3 2/3 65 52 I VQ 
Miford impress... ....0« ah oten atte 4 y% 65 52 H M 
mrords impress film <.4.....+-+0. 2 1/3 90 63 VQ 
Wiford Ohromatic .. occ. succes - 1% % 130 72 M 
Ilford Special rapid ...... eststacets Mir L 1/6 180 87 MS 
Ilford Special rapid film ........ 1 1/6 180 87 MS 
Ilford Screened chromatic ...... ¢ if 1/6 180 87 G MQ 
Pitord sol) film.) 6 6+ aneacog oA % 250 100 MS 
Titord Spec, Tap. Ean. <.-'. . erat rere smneie % 350 120 F Q 
fOr erAWLO-SCLECN sciescle 6 cre ee 0 % 1% 350 120 M 
Ilford Rapid chromatic .......... 34 % 250 100 MQ 
Hford Ss... Ext, Sen. ......'. Aare RE 1/12 350 120 E MS 
ICOM Zeno A400) csc oie 6 eo 5 soe y% 1/12 350 120 K MS 
Ilford Zenith film ......... era ee, ky % 250 100 MS 
Wilford] Press... «+ Pea eea ana, ance 3s » 1/12 350 120 D NS) 
PILOT OM MONSPCD yy 20 6 ss. s.0:0 6s 0 0 os yy 1/12 350 120 D s 
Ilford Zenith 650 ..... Bae bits sae ae, 1/16 500 143 C MS 
Ilford Zenith Ex-Sen. film ....... % 1/12 850 120 VS 
HMIf6radersOrZenith se. ces ess s AOD. 1/16 500 143 MS 
Illingworth Ordinary .........- ers 4 uy 65 52 I VQ 
Illingworth Med. & Ortho med. ... 2 y% 90 60 jaklk 9 CALAIS, 
Illingworth Pan. Process ........ 4 a! 65 52 VVQ 
Rilineworth Sp. Tapid <..essccees 1 1/6 180 87 G MQ 
Illingworth Non screen .......... 1 1/6, 180 8% 4G VQ 


58 PHOTOGRAPHIC FACTS AND FORMULAS 


Amer. 
Phot. 


Illingworth roll film Pack ....... 1 
Illingworth Panchro fast ........ % 
Illingworth High rapidity ....... % 


Illingworth Ultra rapid ..... ave 
Illingworth Studio fast ..... Missiles i ee 
Tltingworth Fleet... ... Ae em ne 


Illingworth Studio ex. fast ...... 
Illingworth Super Fleet ......... % 


Illingworth Ortho fast ......... 1% 
Imperial Process ........ pieleiete te 9 
Tmperial Perocesss 60.9 cc cle sssieysi< = 4 
Imperial Landscape iii. c.+ elelets) ss 6 
Imperial Fine grain Ord. .. as 6 
Porperial Ord. bs lieeke esis ts ol evs Sechaba 4 
Imperial Sovereign .......-ss00. L% 
Tmpertal (Speci TAan 2 ac acetone ak ee 
Imperial Spec. rap ortho ........ 1L 
Imperial Non-filter .......... euste 1 
Tinpeérial: Roll Alm i.\5, 2005. ae 6 le 
Lmperials PanchrowA tines sinate sien A 1 
Imperial Panchro B ....... POR 
Imperial Special sen. ..... SL Pann 2,” 
Imperial Special sen. ortho ..... 4 
Imperial 8. §. Press & Flashlight . % 
Imperial S. S. S. Press..... SRN 
Trmperial Nelipse: [4/258 foxes oes u 
Imperial Eclipse soft, ortho,orthosoft % 
Jougla Rose label & ortho A ..... a 
Jouglay Intensives cia ieee pie els ele o 1 
POULLA Ortho Sy Gal mace seein: 1 
TONGA Pane \PTOCESB atseiesis cteaieie e 1% 
Jougla Blue band & Prof. ........ if 
Jougla Green label ......... Sy REY 
Jougla Mauve band ....... alte tackle eae 
iodaky Speed film? . teu. scene PS oak A 
Wodak iillm pack os tte cre PE | A dlns/% 
Kodakveutchime rer mantle siete 34 
Kodak super speed ......... Me eiein se 
Lumiére Blue label ....... sisiswe sie) LUG 
Lumiére Simplex, anti-hal. ......1% 
umVere  OTtHO VAS) sealer eee 1 
Lumiere) Ortho nO vc sere ese ters aie 1 
Lumiére Pan. Procédé .......... a 
Lumiére Reproduction ...... ete tens 2 
Lumiére Pelliculaire ....... Bie tates 
Lumiére Instantanée ............ 1% 
Lumiére panchromatic .......... it 
Lumiére Extra rapide ......s.+». 1% 
Lumiére Grande instantanée ..... 1 
Lumiére Portrait instantanée .... uf 
Lauamiére Maxima. ipsa ss le ks bis, arog 
Prumitre Sigma: oy seen oni % 
Lumiére Autochrome ....... 7%-8% 
Lumiere’ Plavik: film .ac.-c. sake - 1% 
Tumiére: Cine! film (sean as seen 1% 
Lumiére N. C. Speed film ........ 1 


B.W. 


Wat. Wynne Har. 


180 


87 


OQ] 20 SSSR ORePHR HARPROOUE eee 


aAWOOY 


Ow 


< 
DnMmM mM 


Sooke 


EXPOSURE | 59 


Amer. 

Phot. B.W. Wat. Wynne Har. TDs: 
Lumiére Sigma ortho film ....... 1 VA 180 87 Ss 
TAT IORI TOCESSiteisieic acs s/s 0 010s 0.6.0 9 4 32 85 H 
Marion Fine grain ....... ares’ 6 2 45 43 M Q 
Riarionue Ordinary. “.< ce's se 6 sise's ae 4 i, 45 43 H. MQ 
Marion Panchro ......... Rove ate ee (red % 250 100 F MQ 
Marion Inst. & Iso ............. A 1/6 180 87 G M 
ER TLOMMISTRLITATICY «6 steles's sess sere) ek % 250 100 F MS 
Marion Record & Iso Record ..... % 1/16 500 143 O VS.S 
EMEIOD HP 32 65, slale'. oe vials eee ee 1% 250 100 MS 
.-Marion Portrait ...... Brae Ri oh were Lye uy 130 72 M 
PBPIOUO Wes odds asccesva LY % 130 72 MQ 
Mawson Photomech, .......eeee0.8 9 4 382 35 Q 
PIT CAN GL GMs ice gietels «sles 6 0 0 4 1 65 52 I VS 
Mawson Felixi .....cccccsceces 1 1/6 180 S77 eG M 
Mawson Gladiator ..... Sividiavels ayo ite 1% 250 100 E NS) 
“Mawson Ortho A & Pan. ........ 1% % 130 72 F.G MS.VS 
Mawson Wizard ........ AIS Gaara 34 1% 250 100 E MS 
Mawson Victory ..... eetgreliNeterec ss ut % 180 87 E Ss 
Mawson Super Gladiator ........ % 1/12 850 120 VS 
New Record, ext. fast .......... % 1/6 250 100 M 
INOVOX EXE, BPCCdyY c...scrcccsvceee % 1/6 250 100 F Ss 
PROMGRGODCNO ce vigifses Geis sles sce 0a 6 1 1/6 180 87 F M 
Mlovex OFtho studio .....ccesvees % % 250 100 E MS 
PIOVOS RIGS SPCOG. cs wevdscvecce % wy 350 120 D iS) 

PAE CLECOLOT DLAbO. «ccc sacs 0's eee 5 4, 11 21 
Pare Oe ME ot ialiar a. 6n6 616 :s.0) re 6.061086. 2 yY, 90 60 MS 
oD a a a y% 130 72 Hf MS 
Raleh PLOCGsS Pan: 22s... veces 2 yy 90 60 M 
Peeeeee er OFTthO eee ccc wcrc ees 6H % 250 100 Ss 
Paget S. R. & Ortho 8. R. ...... vi 1/6 180 87 G Ss 
Paget Prof. Med. ......eeceveee 1 1/6 180 Sia sh Ss 
Paget Ortho ext. Spec. rap. ..... % 1% 350 120 VS 
Paget Port. & extra SS. R......... % 1/12 350 120 &E s 
were fOr OXte Re cect ces coes§ 1/12 350 120 E vs 
A COCMLOl MAIN |. sc ccce od ole seis ace 1 % 180 87 VS 
REA OOtO EE OLGHO. ccs ccc. cee oe 1 % 250 100 MS 
PeacOtelaDaOrd. re scsi cec cv seee LD % 130 72 MS 
PRGSt PLUITICANG 2... cc scecessae % 1/16 500 143 0 S 
Rajar Ordinary ...... GIRL CAR 4 % G5 ss be I Q 
Rajar 5. R. & Iso N. 8. ........ 1 2/7 Goer £80 87 «6r#F M 
Pepe reerOl let limarets aciele stereo e690: 008 1 % 180 87 F MS 
ajar Ultra fap. 400 .....c00.. % 1/6 250 100 E M 
ieajere Ultra Tap. G50... cs rcee 1% 350 120 M 
MOCO ETOCOSS! chil crere bv sicleres 66 cies 9 3 32 85 L Q 
Become anGhro, (ssc ccldis's « We ete” a 2 1 130 72 J MQ 
CY Ee ee meteeste iets tis or 6 ob LL % 130 72 H MQ 
Ged OTENO Ti ccc vee ivvccsess LH 1/6 130 72 E M 
seed 26x & Non-hal. ......cccs2. % 1/6 250 100 E M 
Heed Gilt Bdge 30 .....ccnccecee % 1% 350 120 D MS 
Seed Graflex ..... Sere hee te a ee ENS) 5O0n? 142". (0 vs 
Peanaara imp. Port. ..c.....c00. % % 250 100 M 
Btandard Postcard .......c.cees. & % 250 100 H Q 
Standard Orthonon & Poly. ...... % 1/6 250 100 E M 
Standard Ext. Imperial ......... ™% 1/6 ° 250 100 E MS 
Stanley Commercial ........20.. 4 1% 65 52 H Q 
Stanley Regular ......cccciicee % 1/6 250 100 E MS 


60 PHOTOGRAPHIC FACTS AND FORMULAS 


Amer. 

Phot. B.W. Wat. Wynne Har. TD: 
Wolcaned mie worck i. ci otelorsrevelctetel tere 1 1/6 180 86 vs 
Wellin afore elimi tor, fecatte ites te ate! a eka 1 % 180 86 M 
Wellington Ortho Process ....... 9 1 82 85 M VVQ 
Wellington “Ordinary “cit. s.c'\ <1. 4 1% 90 60 Q 
Wellington Speedy Portrait ...... 1 1/6 180 86 G M 
Wellington Extra Speedy ........ %4 1% 250 100 F M 
Wellington Iso speedy & Anti-scr. . 1 1/6 180 86 F M 
Wellington Studio anti-screen .... % 1/16 500 143 EB MS 
Wellington Press & Spec. extraspeed % 1/12 350 120 F Ss 
Wellington Xtreme ...........0- y 1/12 350 120 E Ss 
Wellington super Xtreme ........ % 1/16 500 143 C VS 
Wratten Panchro,... 7 c.s © cists 1% % 130 72 MS 
Wratten Panchro. Process ....... 5 % 65 52 
Wratten Panchro. Mi... 320... 5 % 65 52 


Exposure——tThe following table shows the exposure cor- 
responding to the number found by adding the five factors. 











3000 F005 2300 : fi Eo 1230 
S 1 S aeeo Ss 
6 Ivo 63 7d 7 500 2 3) 8 zh0 
2S S 1.8 S 1 8 
8: tbo 9 15 2; 75 10 BO 10; ts 


ee |] ee | || —— 








i ef ef 





72 
215, | 23, | 22% | 24] 23% 
23:4) 94” | 24; | 2b ae eee 





264 | 26." | 27™ | Oya 


30: ¢ 





28; 4| 29" | 29:%]| 30 








> 





EXPOSURE 61 


CoNTINENTAL PLATE SPEEDS.—In the following table the 
speeds given are those usually accepted on the continent of 
Europe and are “degrees Scheiner.” A few plates, other than 
those of German make, are also included. These degrees are 
compared with those of other speed marking systems in a 
table on another page. 


2 OS AS ne Wes 
0 nat) 0) 2 ee 1225 
SU TRO MISOTANIC. 6 5. ccc obese canis c wes ees iy, 
re eat Line as Goad a Gee Seisie okie eee ye 17 
ESD SSS SES 15:5 
MMPI ER 2 is oa Wak cig 8 els ca Slee vis oie ene 155 
CE 20 SS us 
ok LEC cao PeG 6 Cea ene aes 
NM eis 5 iss sce cts pee w esta ees 17 
EI EOC TON ISOlAT cio. kids oes sc te sels wees 12.5 
SAE Ao 2 a 15 
Se eG A 15 
RU CME se Ly swale sie ee ee soak ee ees 17 
TERN CLO ia ssp ccs ss be ees bee ewes 20 
Aas CEOS 610 0): Dol 1575 
eC A CF 2 ioe cc pcsc sce ceveeeveus Wy Rs 
MP MRIECOIALG F656 noe eos sd oe day elvis co 'ls 14 
Been re CCOTU Ki es oe ed sk lee ee L825 
Beererimamitra-ecord: Wes. ek. ee ee ee ee be 12 
a Le VN I ee 15.5 
ermoriayenow label ortho... 6... ie oe eee he ole 14 
foniasvelow label ortho antihal: .........0...5.- 1 
Me eOGIADGle hey. ss iis. 8 2 dass te doe doen de hea th AZ5 
MPEP EEEAUOS. coy Gos coc 5 pf vee dele soc deleloue’s 14 
SSS Pr ee Zs 
UE Ay Coy cs ho, sv bo asc ae se cu ees 125 


Ee es cee aia'c od viele el ecalnlend ola le Gobo aie 17 


62 PHOTOGRAPHIC FACTS AND FORMULAS 


Bastman SiUy Ro ooh. cs lala ie el ee 15.5 
Hastman Seed’ 26')4 i460 aes weve ek oe 12.5 
Eastman Seed! 27 wits. vb Nir ba 14 
Eastman’ Orthow. i. a ee Ok oe 12.5 
Bitwee ‘Color wi wie a a 2 14 
Eifwee Garantie... ogc cube ve aloe Sg 14 
Effwee ortho. antthal.. ... 0. 0..4\s 5 se ee 14 
Eifwee Special. oe. ecco oct 12:5 
Efftwee Ultra rapid! .........:. 1... 22 een 17 
Fisenberger: Extra Rapid. ........ 250 14 
Eisenberger. Color... 2.00.5 Jas. stea) > oe 14 
Eisenberger Ortho antihal’... 2. .o. 2 2 14 
Eisenberger Reform |... 6.22 ....)..- 25aa er i 
Eisenberger Ultra rapid: .).... . 205.5 sia 17 
Elko Ultrarapid 10.00... 0. 00. y 3c ie 17 
Elko Ultrarapid antihal.... 2.2.0... 23 14 
Elko Ultrarapid ortho......00.0. 0 (2 i534 
Elko Ultrarapid ortho antihal.,..... 2 eyes eee 14 
Ensign Filmpack & Roll film...) 17 
Errtee Yellow, label... 2.0.0.2 0.lon ea 15.5 
Errtee: lilac label...) 005.04. or 17 
Errtee white label... 00. 0.00.2. 000. Lom 
Glock Fidelitas : os... sc Ge tale o sera 14 
Glock Bona 2... c.a00. eee eo, oe 14 
Goerz roll film and film pack... 22. <4 yen 15.5 
Guilleminot .Radio-brom...: . ...)... 2a ee 18.5 
Guilleminot ,Radio-Eclair .... 5... 23 ee 20 
Haake High speed portrait 00. 0... 17 
Haake Normal... 0.00. osc sca. + ote 14.5 
Haake landscape and. Process |...) 2.2 16 
Haake Ortho \25:2%, Jn Us Ga peace ae Sere ns 17 
Hauff Extra rapid es. 6.60. a0 ee 17 


Hauff Orthochrom extra rapid... 2. .).)eeneeee 17 


EXPOSURE 63 


gre remchitom antihal, .\. 0.2.5.0... 060 .ee elses 17 
i. oie ee a ce dee leased 15.5 
LN eS SEG 0s Fi 20.5 
ee a ks wo spel dss ein Sb ON cae 19 
BME PE TONSEATCUCY ee bested leaders 5 
MP CTCTIVAMIA: 05.5, ans oye tele eels bes aenwls oe 12 
go's ss ss inp Whabiw > tol via FIRIR 16 
Meena ira ortho & Antihal........0...0.205.. 15 
ie UE a lp Sa a a ge 16 
PregenrorOrno-Vigor antihal. ........5..... Pee 15 
feraneo .iz0, orthochrom antihal ....:.....4.... 13 
fietianpolarot, orthochrom antihal ............... i 
EEN i, ics Felines bet lle eae see oles je 
Perianeo Germania. transparency ........6.......5- 1 
Me GIO OII sy 6b hols wk ae edb oe le eles eis 
0 TEL eB 0; (a |e LZ, 
(os SONS Gn ESS 52 0 @ ane 152 
Re OLA BUPOTONO Gin). delete ce ek ee ee ee es 14 
Memmmemerartia ce ortno antihal 0. ed ee ha ee as 14 
NEEM Ted ee ols cn so cie Ae Sows oo aie 14 
Potro cessopian filnipack ....... 0600. es ee ee lie 
NN Fg gh 6 ioe ws eats ae VG oe slldiw'a’s Ss 11 
oh NOU Ge St ES 0 ng oo 18.5 
Mee IG. eel cle ee ie Sd eae We 14 
LOE Te CE 1. ce CPIM Nas, SO 14 
PP eaOTENOLG. ANtthAl 2... ea heb ec cen 14 
Jl. (BG ee LN LEMME SP aN oe ere ROLLE 125 
MR Ti ge ies 5 oh oe eA Od ee bes 14 
Mics? Niles aia acs nbs Hewes be we alles 125 
ee ALADIC) 65. ovis os iss oe ok we sel So Okla 17 
SE SULA <6 Gg gel eater ea 14 
Se BOLE E TG i ig, oi ah.c.n'd cua ein. we eg ts ale egahave’a 17 


64 PHOTOGRAPHIC FACTS AND FORMULAS 


Ilford Versatile... se in oe br leles eee 18.5 
Tford’ Zenith 6 ies cick sew & le Ces ee 18.5 
Imperial Flashlight: .....0...5.... 5 +s er 18.5 
Imperial Ortho spec. sen’. .....5 +. + 2s ne 17 
Imperial Ortho spec, rapid ........... <2 eenee pelos: 
Imperial Special sensitive ...... <>... - eee 7. 
Jahr Sigurd ord, all sorts ........... 1.5 15 
Jahr Sigurd ‘ext. all sorts... ... ..... 5.20 18 
Jahr Blue seal... 0 e 5 oe coe ee 2 ee 15 
Jahr Blue‘seal ortho........ 2.0.0.5 (22 1 
Jahr Red label, A, B,’C, D>... 3.5 2 16.5 
Kirschten Reform red label}... ... .2. 2 eee 11 
Kirschten Extra rapid yellow label .../2)2.)eeee 14.5 
Kirschten Extra rapid antihal: 2.9, (2g... 14.5 
Kirschten Extra rapid orthochrom .... jae 14.5 
Kirschten Ultra Rapid)... 0. 2.02. 1. ee 18 
Kraco Extra rapid 2. .....)1./).7 0 ee 15> 
Kraco ortho (oo. oc eens Os vee ae eer 15.5 
Kraco ortho antihal... 2... 60.0... se 12.5 
Kranseder Reform >. 2... . 5.4. 7.1.) 1a eee 12 
Kranseder ortho. moment .../....4¢. ee 15.5 
Kranseder ortho. slow. ......... «+ +4 0s 10.5 
Kranseder Bromsilber extra rapid . 272) ee 17.5 
Kranseder Bromsilber antihal) ..... 2. eeaeeee 11:5 
Kranseder Bromsilber extra rich |... 2 20s 1535 
Kranseder Imperial .......7...... 2 18.5 
Kranseder Munchener Aerial... J. ee 16 
Leonar Green label. ....4...... 0. i235 
Leonar Lutar oo chge ca os ot one ot 9.5 
Leonar Red label... 00.00.20... 2. 4. ee 14 
Leonar ortho & antihal ............ J) eee 125 
Lainer Ala ooo. dues eaic's ce cass 0 5 eee 15.5 


EXPOSURE 65 


MPRRC PP ATOCUIOVANLINAl 5. ce cee cee we we ties wes 14 
CROC eg we es ke vis ssc e eee ce cess 17 
MOL CATAL, ous ccc ec vcs ee esceenees Wey 
SREP Re antinal kc e cet ee es ewes 12.5 
ey wa csleieis nes eae eeaeces 25 
NEM CMe lee ale) oid o's <0 avs <iscee ssiee 96 40 17 
voy LET er sg) 00) 2 Be a 14 
Lomberg Elochrom antihal. .......... Se ete Mee eek Pan 
LO ial os 
Mmnemeroeiandscape w Repro. ........e50scesecees 9.5 
MEP CTAB ie cn sc vig vic hse eve tesee eee nee 8 
ss he GENT ad a 17 
eT CHESCTISIIVE (oo... ec es ecw es esssge Liss 
RemroT Ove Aitilal . 60... cee ce cece te ee eees 14.5 
Serre OXtTA TApId 6.5... ke eet cea eae 17 
(no) Ue S56) AC a 15.5 
ME eGLtO Weatiinal, . 6... tet ce ee tence enees 14 
a WLS 5 cece 15:0 
Ee CHOW RIADCI O octs ss sve ee ees es ste ce eee ae 
TM A pec eye dcctcsecccccssce 17 
SODAS ES Co sat er La 
EU OSCOALCU Sg oivec daisy soc wee ccc eee ele eee 15.5 
SES ME ECM A haigiehs le gis c els cs aise ote s ssie'e 17 
NRCS eal ok yc UA Sa aa 11 
cn Pe CN WTE el 2 haa 1235 
Ot git wee ys ce viet oiesa este eee 14 
RPO oes 5. vc 5 ca vaca ons cg ele eens 18.5 
MEE PEIMECALIVE DADET {i ics sce ecco seeees 10 
aE eA Pee iy yey dial d cb cceeie cu o.0 eie'e wi wees 14 
Las c pa RULES Sy Se ar a eee pa 
MEE URFE RO EE CU e . os. oly tits vip p a tcdewieeegle sees 14 
RUC GTITEGSCLCETL os. os ce ed boa e ee cs ele aes La 


SS 2 a NS 17 


66 PHOTOGRAPHIC FACTS AND FORMULAS 


Perutz Perxanto) 2. 08 0.05.5 0s os ee eee ae 14 
Pertitz Silver eoside 5.004 63.4 va Ope pe 12.5 
Premo film pack 2.0.00... sa La 14 
Premo'film:pack Speed). .54.555.5 0. oie ae 15.5 
Sachs Bxtrai rapid ii... cesia «Gs one ee 15.5 
Sachs: Goloris iiss ac. Ads y dh see ee 14 
Sachs. Antihalation 005.4425 2.4 see 12.5 
Sachs Antihalation Colors... 4.45). eee ee 11 
Schleussner Blue label»... 04)... 5 2. eee 17 
Schleussner Yellow label | 0.5... . /2.cae ee 12.5 
Schleussner Yellow label Instantaneous ............ 17 
SchleussneérInalo . 6.0.0.4 e's doa enue ee 153 
Schleussner Orthochrom ..........0.eeeeeeeceeees 15.5 
Schleussner’ Red label: 2/0... 0. saree ee 18.5 
Schleussner Viridin). i... 6 ..lb anv as oan 17 
Schleussner A inalo os... 0.3 on. 5s 17 
Stock Extra) rapid o....4)05.025.0 32st 17 
Stock: Ordinary .\.).502..04 04's. 4 Se 14 
Talbot Errtee Special rapid >. J. . 2) Spe 16.5 
Talbot Errtee Ortho & antihal’.. 0.723) eee 15 
Talbot Errtee Extra sensitive 2... yy see 16.5 
Talbot Errtee Ultra ‘rapid ..,.).. 4) ee 20,5 
Unger & Hoffmann Verax normal’). 25a 7 
Unger & Hoffman Kromal.. 2... 17 
Unger & Hoffman: Verax rapid 2... 20 
Unger & Hoffman Verax rapid with Star .......... 20.5 
Unger & Hoffmann Verax: Bromide 732. ee 18 
Unger & Hoffmann Verax Isokromid .............. 18 
Unger & Hoffmann Verax Transparency .......... 7 
Westendorp & Wehner: Red ..2). 2... Ge ae. 18.5 
Westendorp & Wehner Green |... 02.) pu eee 14 


Westendorp & Wehner Color... .. (uu 17 


EXPOSURE 67 


MEPIS ADI cre ce sce ede ee ee cosesees 14 
a Loy here er Wale) [sa 14 
NRE ER EPA TINITIANG 0052s rey ccc care lees cates eee 125 
OE GP Tete. eo sc eeen bau e sledge gee ees 20 
BROMIDE PAPER SPEEDS (BURROUGHS-WELLCOME).— 
NE EMR ay vcs e cid eva cvielt ee cesecdea's 4 
MIME A VON 6 oko. Sicuine ovis esc ec ees sieeve 4 
Barnet Ordinary, Platino-matt, Cream Crayon ...... ly 
MIC CEM LON CUC 5 5 4). tases se asiels sees eecens 2 
Ro fay ois. ndn wis n.aieu ee others evince ws 6 
EET ae c)6°5, O'S pos ain as pia, «vi dis ejele a e's dns 6 
RT oy) <6 dgie a4) < site else tie ties soecaladie 6 
RE NY itn inn nia ee) pialejave seis viens scales)» 12 
ME ig iii cis, oi e/a aut) c ts wie Pests, sels boon en Z 
memerionat jatino-matt, Rough ............6.0s040. 6 
Te cision oe sess elk Vi gw Sie die oie lees 48 
SU ‘es REI Pe a 2 
ea bes ole 6 10 
MME ETSI 54 cg ova ave w'c hols vis v's acssecnie's l 
MM Sy kyo leldit nc o'eie peas ous eves’ 4 
NE AMMA ols cia gins edie cle sian es velene'es's nes 24 
SP eee a espe ccs cies eesves Pe 
arora stauyaricties except as below) .:...:........ 3 
BAC ONITASEY oe. ooo csc nc eines sn oislese ewe Z 
PINCIETATYOSUTIACE oc. ce ne se ccc ee neeues 6 
SRL oo a A Se 2 
IE HALINO-INAtE gon ie sc ee cc ce cine decuevece 1 
REE EPTINCY  aie ac dns ss css be Cas pneeeue 1 
i OS a I na 2 
Nore a lsikis as on oie se dine ee ed weleless 16 
I eos 2 is cielo sje wines eine cea ewe e's 64 
EMD VE ree) las 5. ss Sve ciaseyesclesd.e celebs eeeun te 1yY4 


Kodak Rapid (Platino-matt, Permanent) ........... ly 


68 PHOTOGRAPHIC FACTS AND FORMULAS 


Kodak Contrast (Platino-matt, Permanent) ........ 4 
Kodak ‘Slow so on as isola so el ee 6 
Kodak: Nikko, Velvet: ov 00s scl ossis eee 3 
Kodak Kodura oo i Siti oes ve be eee 24 
FROSIMOS seule ig oe sleidc as wipe eee ao ks lege er 3 
Kosmos  Vitegas. os. iieieece eeiels ole « wale sees 24 
Lalywhite, “Normal. ..).:. 54 «252 0.15 «)-. sr 8 
Lilywhite,; Rapid... 60.05 ca). 2 1 
Lumiére, A, C, Fy) LU oo... 5 eee oye 
Lumiére; Bo... a eo a ee een 2 
Marion ()...00 6. ee ak oe oe 6 
Montatik soca eee ies sete cae ee ote er 2 
PASO eis i005 Gas ne oe bic Talate le 4 Se 0s le ele 1y% 
PooMy Gy ec. als Gewese viele eee er 6 
Rea par crac e nice oa y solace e's 9 te ine mse phe br 6 
Standard Bromide & P.M. C. .... 2. ene FAN 
Wellington 2... sce. es ee esas cs ds ly, 
Wellington B. B. . on. 000. atone ere 6 
Gashieht -papersii) yo o 6 ce eee ee approximately 64 
LANTERN PLATES.— 
Austral oo... bsees cs is cn ns ew ee ee ih 
Barnet if... ces. sas bel ee ei wee op 6 
Cramer Lantern, Transparency: ..2.2)0 eee NO ee) 
Fastman. o..006 see vik cis se ae 6 
1 Dkrs)$\t ee UN 12 
Gem: Black .' csc 0G od aie lense or 10 
Hammer, Yellow label ..°0...0200 (7) 3 
Hammer, White label .. 20...) ee Zz 
Ilford Special. ..s.. 05.5 .4555. 050 se 5 
Imperial. Special 2.0.3... ..2 40s 916 66 Se a 
Imperial, Slow ....45 0.444 Gus eu es eee 8 
Jougla Black 2. .....0..4 64. 005555 oer 8 


Teta... cscs pices ary cele eves sie dc cel teeta 6 


EXPOSURE 69 


mameeceeuransnarency, Blacks... 6h. c 6 ese cece wee 8 
MRE SM os oly wo uc a a eis aie ev se eis oie 25 
TEES se 8s a a 10 
eRe IOTOSOLONNGE 6... iva ce ce cle ces ase en see 4 
UIE NOM icc). cia c selec esses eleisles eset ee es Jz 
Meemonmcrelatino-chloride ...... 26.6.0... 00sec seas G2 
NN en erie ee cede eee es 4 
ee AGL S05 ne ly 
(Dl UTS rg Pa i 12 
POMOC R TANSPATCNCY ooo. ics nes ce eet ecto e 5) 
5 Pn os aod ry ler are 10 
IRM EAU ACK fori oss bie s ee a ot eatin oes tebe s 8 
A cS ope 3 
LSS Go eg a 
(ie) SSS, oil pel a 4 
STL 34 oe SS 1 
Rete TE eee so og al vine ge Gis 'es eee ein e's 20 


In these tables the paper or plate with a factor number of 6 
requires twice the exposure of one with a factor of 3, under 
like conditions. 

COMPARISON OF PLATE SPEEDS.—Unfortunately, no com- 
mon agreement has been arrived at as to the marking of plate 
speeds, but the following table gives the usually accepted 
ratios between the various systems: 


m S a H Be of 

nie 5 s z3 ee) pe ene et ales 
5.4 8 17 8 8 Cc ve 100 
J 10 20 9 b 80 
9 15 2O 6 9.5 a npae 65 
11 16,5 205 4 10 1 43 50 
14 Pil 29 a 10.5 vs 46 40 
17.5 26 o2 3 ab 3 49 30 


70 PHOTOGRAPHIC FACTS AND FORMULAS 


: 6. og). ee 
hid; E fd E B Ste cn 
23 Rae nh 2 212 “as ern 
28 42. 40° 2. 13 
38 52° 48 134 14) 6 
45 661 52 115 °° 7 eae 
56 92° 58° 2/3 16) se 9 
70... 103. 640 a 7 rr! 7 
88130 72-0 4) 18 oes 5.5 

105... 184... 79. 6) 05) Ok ee 4 
140... 206. -90°' (1/3 |) 20) epee 3.3 
175.257, 100...) | 2a 2.6 
228.335 2. 1150 | SoS 22 2 
280°. 410.128 ..1/6. 23 See 1.6 
350... 575. 144... 1/8 . 245) ieee 1.3 
455... 670: 164.) ..4.) 25 1 
560. 825° 180 1/12) 26 4 91S 8 
700. 1030. | 204...) 27 S00 ee 6 


875 1280 Gi 228 Sele 28 ZO 0 


To convert Hurter & Driffield into the Watkins system: 
Multiply the H. & D. numbers by 50 and divide by 34. 

To convert Wynne into Watkins: Multiply the square root 
of Watkins numbers by 6.4. 

To convert Wynne into H.& D.: Multiply the square root 
of Wynne’s numbers by 7.7. 

This table gives an approximation of the connection be- 
tween the various systems of determining plate speeds. But 
absolute reliance can not be placed upon it as there is no 
standard system and plate manufacturers differ as to their use 
of the Hurter & Driffield (H. & D.) method, therefore, these 
speeds, as advertised by various makers, are not comparable. — 


EXPOSURE 7\ 


It should be recognized that the figures given are for use 
with particular exposure systems and will yield good well- 
exposed negatives. The character of the same may not agree 
with individual opinions, and in this case higher or lower 
numbers should be used until with a given developer the 
desired character of negative is obtained. All plates have 
more or less latitude and, therefore, considerable variation in 
exposure may be given and good negatives be still obtained. 

EFFECT OF THE STop APERTURE.—The relative exposures 
are as the squares of the aperture of the stops or diaphragms. 
For instance, if the exposure with stop f:8 is 5 seconds, with 
f: 16 it is not twice as much, but 4 times; because, according 
to the above rule, 8° — 64 and 16’ 256. Therefore, the 
exposures are as 64:256, or as 1:4. This applies to all 
lenses irrespective of their focal lengths. 

VARIATION OF F VaLuEs.—When copying and enlarging, 
the lens is not working at its equivalent focus, the actual 
working focus being more or less increased; therefore the 
values of the stops are altered. Mr. Alfred Watkins gives 
the following table which shows the necessary variation of 
the exposure due to the alteration of the f value of the stop: 


Lantern slide making Thin Neg. Medium Dense 
Neg. Neg. 
Copying Black and Photograph Coloured 

White Object 
15 times focus from lens 4 YY 1 
iA es 7 ae YY 1% 
Pe HX wo WY, 
3% 6é 6é 6é 66 yy 1 v 
ee KK ee 
2yY 6é 6é 6é “ce %4 ly 3 
ie 6é 66 6cé 66 1 ‘ 2 4 


(Copying same size) 


72 PHOTOGRAPHIC FACTS AND FORMULAS 


The numbers in the table are multipliers of the calculated 
exposure. 

VARIATION OF ENLARGING EXPOSURES FROM THEORETI- 
cAL.—Mr. Watkins also gives the table for enlarging: 


Enlarging 
Diameters Thin Neg. Medium Neg. Dense Neg. 
Equal size 1 2 4 
ly ly 3 6 
2 2% 44 4 
2% 3 6 12 
3 4 8 16 
4 6%4 12% 25 
5 a 18 36 


These numbers are multipliers, as in the last table. 

The numbers of diameters of enlargement are found by 
dividing the length of one side of the enlargement by the 
length of the same side of the negative. 

THE EFFEect oF ALTITUDE ON ExposuRE.—Variations in 
exposure due to variations in altitude, or distance above sea 
level, are negligible in ordinary work, that is to say, unless 
the altitude exceeds 5000 ft., when three-quarters of the cal- 
culated exposure should be given. Over 10,000 ft., half the 
regular time would be sufficient. This is for near objects. 
Panoramic views from mountain tops require panchromatic 
plates and special filters to cut out haze, as in aerial exposures. 

SHUTTER SPEEDS FOR Movine Osyjects.—The following 
are approximately the slowest speeds of the shutter which will 
give a sharp image. The object is assumed to be 25 feet 
distant from the lens and to move diagonally across the field 
_ of the lens: 

People walking in street:scenes ..... eee 1/10 sec. 
Animals and people walking slowly ............ L/250e 
People walking three miles per hour ........... £/50.< 


EXPOSURE 
People walking four miles per hour ............ 1/100 
Meniciesiat eight miles per hour ............... 1/150 
Seemicies apten mules per hour «.......6.......: 1/200 
Mrenicles atitwelve miles per-hour ..........3..: 1/250 
MUMEMANCRUOTSS FACES ee ee e's eee cee ie we 1/500 
ie EY ys a 1/600 
Peiomopile and fast horse races .:.....6.0.0-. 1/1000 


If the object is at 50 feet distance, twice the exposure can be 
given; at 100 feet, four times as much. The longer the focus 
of the lens the shorter must be the exposure, and the more 
nearly the object moves at right angles to the axis of the lens, 


the shorter the exposure. 


EXPOSURES FOR INTERIORS.—Cover the camera and head 
with the focussing cloth, and wait until the eyes are accus- 
tomed to the dull light. Stop down until detail can barely be 
seen in the deepest shadow in which full detail is required. 
Note the stop, and consult the following table for the ex- 


posure at f:16 of a plate or film classed as 1% A. P.: 


Stop noted Exposure at f: 16 
aS 56 minutes 
Peel 28 minutes 
AG 14 minutes 
Tale 7 minutes 
(eae y4 314 minutes 
~:45 134 minutes 
f :64 52 seconds 


For other stops or plates, calculate from the known speeds, 
remembering that each step in plate speed represents 50 per 
cent, whereas each listed stop represents 100 per cent varia- 


tion. 


NicHt PuotTocRaPpHY.—Exposure suggested for trial at 


f:8 with ortho plates of speed 1% A. P.: 


Me CORSUOIW  WINdOWS si ose es vie ead ok ON ES 1 minute 


74. PHOTOGRAPHIC FACTS AND FORMULAS 


Hhiminated sbutldings ys. iaien elspeceae io we 2 minutes 
Open; streets with arc lamps! 20...) eee 3 minutes 
Open streets with wet roadway or snow ....... 2 minutes 
Close istreet: scenes...) JGR pale 6 minutes 
Close street with wet roadway or snow ........ 4 minutes 


Stop APERTURE SYSTEMS.—Various systems have been 
suggested from time to time for numbering the diaphragms 
or stops, but practically only two have survived. In the one, 
and the more general, the F or ratio system, the effective 
aperture is expressed as a fraction of the equivalent focus, 
thus as F:8, F/8 or f: 8, which means that the aperture of the 
stop is one eighth of the equivalent focus. The other system 
is based on f:4 as unity, and the stops are merely numbered 
in fractions and multiples of this. The following table shows 
the relation of the two systems, the latter being known as the 
U. S. system, or the Uniform System numbers: 


Ur S.No: U.S. No. 
fied 1/16 Fee ws 9 
f: 1.414 YZ f:16 16 
a4 yy fr 22.02 Te 
f:2.828 y S228 49 
Tas 0.562 fae 64 
~:4 1 {306 8l 
Fi 1.56 f:40 100 
f :5.656 2 f345:25) Sule 
eae fa Sas ~:56 196 
ih 3.06 f :64 256 
£:8 4 tare 306.25 
Fy 5.06 f:80 400 
Poo 6.25 f:90.5 512 
PELs) 8 f: 100 625 

Stolze proposed f:10 as unit, and Dallmeyer ae . Lhe 


Paris Congress also adopted f: 10 as the unit. Zeiss adopted 


EXPOSURE v2 


f: 100 as unity, so that the larger stops were marked with the 
relative luminosity, which gave as a fraction the relative 
exposures; for instance, f:6.3 was 256, and the exposure 
compared to that for f:100 was 1/256. All these systems 
have practically fallen into disuse in England and America, 
the ratio system alone being used. 

Exposure Meters.—The Watkins, Wynne, Imperial, and 
Beck meters are based on the measurement of the actinic 
power of the light by the darkening of a sensitive paper to a 
standard tint. Scales bearing the f: x value of the diaphragm 
and speed of the plate are brought into coincidence, and the 
exposure is then read off against the time taken by the paper 
to darken. 

These meters should be exposed to the light falling upon 
the shadiest part of the subject in which full detail is re- 
quired. If there is no important shadow, test the direct sun- 
light. If there is any important shadow, face the meter to the 
sky and not to the sun, or use the shadow of the body. 

To judge the matching of the tint, hold the meter at arm’s 
length and observe through half-closed eyes, and note the 
time when the paper is neither lighter nor darker than the 
tint. An absolute match is not required. 

MAKING PAPER FOR ExposurE METERS.—In order to make 
a paper suitable for these meters, bromide paper should be 
immersed in the darkroom for 5 minutes in a 2.5 to 5 per 
cent solution of potassium metabisulphite or sodium nitrite, 
rinsed and dried. The tint caused by the action of light varies 
with the paper ; but a test should be made by burning 2 grains 
of magnesium ribbon, coiled into a spiral, at a distance of 
434 inches. The tint thus obtained will correspond to the 
correct exposure for a plate of Watkins’ speed 1 exposed at 
f:8, midday in June sunlight. The colour should be matched 
with water colour. 


Development 


FAcToRIAL DEVELOPMENT (Watkins).—There is practi- 
cally a fixed relation between the time of appearance of the 
image.and the total time of development to obtain a given 
density, degree of contrast, or gamma of a negative, which 
holds good for all variations of strength, amount of alkali, 
bromide, or temperature, within reasonable limits. This is 
known as the factorial or time development method. The 
total time of development divided by the “time of appearance” 
of the first signs of the image, exclusive of the sky in lands- 
scape work, or a white collar in a portrait, gives what is 
known as the “factor” of the developer. The following table 
gives the factors for various developers for a normal neg- 
ative: 


Adurol 5 Kodak portrait 18 
Amidol 10 Metol 30 
Azol 30 Metol-hydrochinon 14 
Certinal 30 Ortol 10 
Diogen 12 Paramidophenol 16 
Edinol 20 Pyrocatechin 10 
Eikonogen 9 Pyro-metol 9 
Glycin-potash 12 Metoquinone 30 
Glycin-soda 8 Rodinal 30 
Hydrochinon with bromide 5 Synthol 30 
Imogen-sulphite 6 


The following are the factors for pyro-soda or pyro- 
potash : 


76 


DEVELOPMENT 77 


Pyro Bromide Factor Pyro Bromide Factor 
gr. peroz. gr. per oz. gr. per oz. 
4 9 1 0 18 
2 yy 5 fs 0 We 
3 4 44 3 0 10 
4 1 4 4 0 8 
8 Z 3% 5 0 6% 


Estimated factors for American pyro-soda developers: 
Seed A. B. C., no bromide. 11 


Seed pyro, no bromide gt 
Stanley, no bromide 10 
Cramer, maximum strength 6% 
Cramer, minimum strength 11 
Hammer, no bromide 11 
Eastman, no bromide 12 


Should the negatives obtained by the use of the above factors 
seem too thin, the factors must be increased; if the negatives 
aré too dense, the factors should be decreased. The factor 
for a combined developer with the reducing agents in equal 
ratios is the mean of the two; for instance: 
(Pyro = 6- metol = 30) +2=— 18 
If the developing agents are in different ratios, the factor for 
each is multiplied by the number of parts, and the sum of the 
factors divided by the number of parts of developer agents 
used. For instance, pyro 4 parts plus metol 2 parts: 
G4 — 24 and 30 Kk Z2== 60 
24+ 60—&tand 4+2=—= 6 
then 84 — 6 = 14 the factor required. 
THERMO-DEVELOPMENT (Watkins)—While the normal 
temperature for development is assumed to be 18° C. 
(65° F.), it is not always convenient or possible to obtain this 
temperature exactly, and, as the rapidity of development is 
increased with a rise of temperature, and decreased with a 
colder solution, allowance must be made for the change of 


78 PHOTOGRAPHIC FACTS AND FORMULAS 


temperature. The variation in time of development due to 
changes in temperature of the solutions is known as the “tem- 
perature co-efficient,” and is calculated for 10° C. (18° F.). 
In practice it will be found convenient to draw up a table for 
a developer for every 2 degrees rise or fall, which is not a 
difficult matter, as one can use the developer factor and a 
table of logarithms. Expose a plate on a landscape, including 
a portion of the sky, and cut into two, or make two exposures. 
It is necessary to have means for warming up the dish, devel- 
oper and graduate, and also a thermometer must be handy. 
The warming apparatus need be nothing elaborate, a deep 
baking tin or a large developing dish. Fill this with water at 
about 32° C. (90° F.), and place the dish, graduate and 
developer in it. As soon as the developer has reached the 
desired temperature, which for convenience may be 24° C. 
(75° F.), and should not be above 27° C. (80° Ey place 
the plate in the dish, flood with the developer, and note the 
time; watch carefully for the first appearance of the image, 
and again note the time. The plate is no longer any use and 
may be thrown away. It is really advisable to place the plate 
in the dish at the same time as this is floated on the warm 
water, so that the plate itself may be raised in temperature. 
It can be easily covered with an opaque card to protect it 
from light. Then treat the second plate in the same way, only 
this time use the developer cold, and note the time of appear- 
ance exactly as before. If the difference in the temperatures 
of the two developers is exactly 10° C., the temperature co- 
efficient is found at once by subtracting the logarithm of the 
lesser time of appearance from the logarithm of the greater 
time. Should there be a greater or less difference in the 
temperatures than 10 degrees, subtract the logarithm of the 
lesser time from that of the greater time, and divide by the 
difference of temperatures. The result will be the log. factor 


DEVELOPMENT Zi 


by which a table can be drawn up for the developer used. An 
example will make this clear. Suppose that we have a 
developer which we know from practical trial gives just the 
negative which we want with a factor of 10. Suppose that 
we make the above-described trial with a developer at 90° C. 
(48° F.) and 20° C. (68° F.), and with the lower tempera- 
ture it took 50 seconds for the first appearance of the image, 
_ and at the higher temperature 22 seconds; then from a table 

of logarithms we find that the log. of 50 is 1.699 and that for 
22 is 1.342, then: 


log. 50 = 1.699 
log. 22 = 1.342 
0.357 


Now the difference between the two temperatures was 
20 —9 = 11, therefore 0.357 — 11 — 0.0324, which is the 
logarithm of the difference in time of development for 1° C. 
or the log. factor. As we know that the developer has a 
factor of 10, therefore, if the time of appearance at 9° C. was 
50 seconds, the total time of development will be 50 * 10 = 
500 seconds. Then, if we want to find the time of develop- 
ment for 10° C., we subtract the log. factor 0.0324 from the 
log. of 50, and multiply by the factor to find the correct time 
of development. Thus log. of 50 = 1.699 — 0.0324 = 1.6666; 
from a table of logs. we find that this is the log. of 46.4, and, 
multiplying by the factor 10, we have 464 seconds as the 
result, instead of 500 at 9 degrees. If the temperature is 
lower, then we add the log. factor; thus, assuming that the 
temperature has dropped 2 degrees to 7° C., then log. 50 = 
1.699 + (0.0324 « 2) = 1.699 + 0.0688 = 1.7638; from 
our table we find this to be the log. of 58.05, and again, using 
our factor, we have 58.05 & 10 = 580.5 seconds as the correct 
_ duration of development at the lower temperature. The 


80 PHOTOGRAPHIC FACTS AND FORMULAS 


following are a few temperature co-efficients that have been 
determined (Watkins) : 
Pyro-soda, without bromide (Watkins) 1.5 
Pyro-soda, with bromide (Watkins) 19 
Pyro-soda (H. & D.) without bromide 1.48 


Pyro-soda, Kodak powders .......... 1.9 
Pyro-soda tabloid (B. & W.) ........ 2.15 
Pyro-soda tabloid, Ilford formula .... 2.04 
Rodinal, Azol, Victol, Certinal ....... 1.9 
Metol-hydrochinon (0.0.0. (9.2m 1.9 
Metol-hydrochinon tabloid ........... 1.86 
CSL y CU ie. iia ot hl eles 2 2.3 
Rytal nf. SUMO s be pher oes buen ee 1.84 
Hydrochinon 7.2. oh oe: oe 2.20 
Paramidophenol; <3. 00s). 2G 2.4 
Amidol i ilncchs ek) sacl se 2.06 
Ortol Ge Sino eae oe cee 2.06 


STAND DEVELOPMENT.—This is a method of development 
in which a dilute developer is used in an upright grooved tank, 
in which the plates are placed and left for a given time. In 
the early days, it was put forward as a cure for every error 
in exposure, and the solutions used were so dilute that from 
12 to 24 hours were required to obtain normal negatives. 
The only advantages of stand development are that the grain 
of the negatives is fine and the results uniform, if the devel- 
oper be frequently agitated, and no visual examination is re- 
quired or possible. It has been stated that the duration of 
development with the diluted solutions can be calculated from 
their dilution, that is to say, a developer that is diluted 5 times 
will require 5 times as long in the tank, but this is only true of 
one or two developers. Wratten & Wainwright found by 
careful photometric measurements, that the increase in time 
depends to a great extent on the quantity of air dissolved in 


DEVELOPMENT 81 


the water used. In the case of rodinal it was found that a 
plate which required 3 minutes development with a 1:20 
solution, when the latter was diluted to 1: 200, did not require 
30 minutes, but 42, with air-free distilled water; with ordi- 
nary distilled water 46 minutes, and with tap water 52 min- 
utes. Pyro-soda and glycin seem to be the only developers 
that are not affected by the water, but a pyro developer 
diluted ten times requires fifteen times normal to obtain the 
same results. Stand development is not economical, as most 
commercial tanks require a large amount of solution, which 
is, as a rule, so oxidised at the end of development as to be 
useless for a second time. The following are some of the 
developers recommended for this method. 


Pyro-soda (Wratten & Wainwright ).— 


A. Sodium sulphite, dry 5g 3 oz. 
Pyrogallol 1.66 g 1 oz. 
Sulphuric acid 0.21 ccm 1 dr. 
Water 1000 ccm 600 oz. 

B. Sodium carbonate, cryst. 10g 6 oz. 
Water 1000 ccm 600 oz. 


Mix in equal parts. 
Glycin. (Wratten & Wainwright) — 


Glycin 0.833 g Y4 oz. 

Sodium sulphite, dry 125¢ 34 OZ. 
Potassium carbonate 416g 214 oz. 

Water 1000 ccm 600 oz. 
Glycin (Bothamley).— 

Glycin 3¢ 46 er. 

Sodium sulphite, dry 15g 23 gr. 

Water 2000 ccm 70 oz. 


Time 1 hour at 18° C. (65° F.). 


82 PHOTOGRAPHIC FACTS AND FORMULAS 


Pyrocatechin (Bothamley).— 


A. Pyrocatechin 10g 154 gr. 
Sodium se dry 40g 616 gr. 
Water 500 ccm 174 02. 

B. Sodium carbonate, cryst. 100 g 31% 02. 
Water | 500 ccm 17¥4 oz. 


Time, 1 hour at 18° C. (65° F.). 
Pyro-soda (Claudy).— 


Sodium sulphite 3.9¢ 90 gr. 
Sodium carbonate 26g 60 gr. 
Pyro Low 30 gr. 
Water 1000 ccm 48 oz. 
Pyro-soda (Harris ).— 
Pyro lg 20 er. 
Sodium sulphite, dry 3g 60 gr. 
Sodium carbonate, cryst. 12¢g 240 er. 
Potassium metabisulphite 6.5 g 130 er. 
Water 1000 ccm 40 oz. 


Time, 10 to 15 minutes at 16° C. (60° F.). 
Pyro-soda (M unkman )— 


A. Pyro 7 100 g 1 oz. 
Potassium matableutanite 25 g Y4 oz. 
Water 1000 ccm 10 oz. 

B. Sodium sulphite, dry 100 g 1 oz. 
Sodium carbonate, cryst. 100 g 1 oz. 
Water 2000 ccm 20 oz. 


For use, mix 1 part A, 1 part B and 8 parts water. Time: 
25 minutes at 18° to 21° C. (65° to 70° F.); 30 minutes at — 
15° to 18° C. (60° to 65° F.); 40 minutes at13 “tonto aee 
(55° to 60° F.) ; 50 minutes at 10° to 13° C. (50° to 55° F.). 
If the developer be used at half the above strength, the times 
will be: 50 minutes, 1 hour, 80 minutes, and 100 minutes 
respectively for the above temperatures. 


DEVELOPMENT 83 


Rodinal (Munkman).—Dilution 1:100. Sodium sulphite, 
dry, in 2% per cent solution may be used instead of water to 
dilute the developer: 


Temperature Development in minutes 
Cent. Fahr. Portrait Architecture Landscape 
woe fae 14 19% 27% 
21 70 15 20% 28 2/3 
20 68 16 21% 30 
19 66 17 22 31 1/3 
18 64 18 2314 O20 
17 62 19 24Y, 34 
oes 60 20 25% B51 /3 
14.5 58 21 26% 36 2/3 
1s, 56 22 274 38 
12.5 54 25 28% 39 1/3 
Metol-glycin (Jeffcott). — 
Metol 0.88 g 40 gr. 
Glycin 0.44 ¢ 20 gr. 
Sodium sulphite, dry l6¢g 795 gr. 
Potassium carbonate 6.5 g 300 gr. 
Hot water 1000 ccm 96 oz. 
Adurol (Mortimer) .— 
Sodium sulphite, dry 200 g 4 oz. 
Potassium carbonate 300 g 6 oz. 
Water 1000 ccm 20 oz. 
When dissolved add: 
Adurol 50 g oz 


Dilute 1:20; time, 10 minutes at 18° C. (65° F.). 
Edinol.— 


Edinol 45¢ 45 gr. 
Sodium sulphite, dry 228 YZ oz. 
Potassium carbonate 44 ¢ 1 oz. 


Water 1000 ccm 20 oz. 


84 PHOTOGRAPHIC FACTS AND FORMULAS 


Edinol-H ydrochinon.— 
Edinol 
Hydrochinon 
Sodium sulphite, dry 
Potassium carbonate 
Sodium carbonate, cryst. 
Caustic soda 
Potassium bromide 


Water 


1000 ccm 


Pyro for lantern slides (Mortimer ).— 


Pyrogallol 

Sodium sulphite, dry 
Sulphuric acid 
Acetone 

Water 


2.22 
0.228 
0.5 ccm 


1.2 ccm 
1000 ccm 


Time, 5 to 10 minutes at 18° C. (65° F.). 


Amidol (Harris). — 
Sodium sulphite, dry 
Potassium metabisulphite 
Potassium bromide 
Amidol 
Water 


Amidol 
Sodium sulphite, dry 
Caustic soda lye, 27% 
Potassium bromide 
Water 
Time, 2 to 3 hours. 

Glycin.— 
Glycin 
Sodium sulphite, dry 
Potassium carbonate 


13 g 

5.2 g 
0.52 g 
2.6¢ 
1000 ccm 


lg 

6g 

10 ccm 
O0.5¢ 
1000 ccm 


76 gr. 
76 gr. 
1842 gr. 
307 gr. 
307 gr. 
61 gr. 
15 gr. 
32 02: 


44 gr. 
66 gr. 
10 min. 
24 min. 
42 oz. 


250 gr. 
100 gr. 
10 gr. 
50 gr. 
40 oz. 


15 gr. 
90 gr. 
145 min. 
7 eT: 
32 oz. 


30.7 gr. 
76.8 gr. 
153.8 gr. 


DEVELOPMENT 85 


Potassium bromide 0.05 g 0.768 gr. 

Water 1000 ccm 32 oz. 
CoMBINED DEVELOPING AND Fixinc.—This process fre- 
quently crops up and numerous formulas have been given 
for its use. The following are arranged in chronological 
order and the later ones do give some sort of satisfactory 


negatives. 
Punnett.— 

A. Potassium metabisulphite 2g 35 gr. 
Ortol 3g Soret 
Water 400 ccm 10 oz. 

B. Caustic soda 4g 60 gr. 
Potassium bromide 4g 60 gr. 
Water 500 ccm 16 oz. 

Galypo 252 1 oz. 
Water 500 ccm 20 oz. 


For use mix | part A, 1 part B, and 2 parts water. 
Hanneke.— 


A. Sodium sulphite, dry 200 g 1536 gr. 
Caustic potash 93 g /14 gr. 
Pyrocatechin 93 g /14 gr. 
Water 1000 ccm 16 oz. 

B. Hypo 200 g S/O: 
Water 1000 ccm 16 oz. 


For use mix 12 parts A, 20 parts B, and 30 parts water. 
Baker.— 


Hydrochinon hese 57 Oot, 
Potassium metabisulphite I5¢ L15'er,. 
Caustic potash 50 g 384 gr. 
Hypo 200 g 3 1/5 oz. 
Water 1000 ccm 16 oz. 


Edinol , : Fides: 57 OST. 


86 PHOTOGRAPHIC FACTS AND FORMULAS 


Sodium carbonate, cryst. 50 g 
Sodium sulphite, dry 25 g 
Hypo 200 g 
Water 1000 ccm 
Cg 
Hypo 30 g 
Potassium metabisulphite 40¢ 
Sodium carbonate, cryst. 120 g 
Potassium bromide lg 
Water 1000 ccm 
Add 2 per cent edinol just before use. 
Pigg.— 
Pyrogallol 13g 
Amidol 1l5¢g 


Sodium sulphite, sat. sol. 240 ccm 

Sodium carbonate, sat. sol. 480 ccm 

Potassium cyanide, sat. sol. 240 ccm 
Crémier.— 


Amidol 10g 
Sodium sulphite, dry 50 g 
Hypo 125\¢ 
Water 1000 ccm 
Raymond.— 
Hydrochinon 8g 
Metol 4g 
Sodium sulphite, dry 30 g 
Sodium carbonate, cryst. 80 g 
Hypo 6g 
Water 1000 ccm 
Crémier, for lantern slide work.— 
Sodium sulphite, dry I5¢g 
Hydrochinon 208 


Caustic soda lig 


384 gr. 
192 gr. 

3 1/5 oz. 
16 oz. 


230 gr. 
307 gr. 
920 gr. 
IL 

16 oz. 


L15 ge: 
11.5 gr. 
4 oz. 
8 oz. 
4 oz. 


17 er. 
384 gr. 
202 
16 oz. 


61 gr. 
30.7 gr. 
230 gr. 
614 gr. 

46 gr. 

16 oz. 


115 gr. 
19.2 gr. 
11.5 gr. 


‘ DEVELOPMENT 87 


Potassium bromide 15¢ Lib er, 
Water 1000 ccm 16 oz. 
The actual developer is 4 parts of the above, 8 parts water, 
and 2¥4 parts of 20 per cent solution of hypo. 


Haysede.— 
Sodium sulphite, dry 20 g 154 gr. 
Hypo 320 g 2457 gr. 
Sodium carbonate, cryst. 10 ¢ LU aS 
Potassium bromide 10g 77 gr. 
Hydrochinon 25 ¢g 192 gr. 
Ammonia, 28% sol. 10 ccm 77 min. 
Water 1000 ccm 16 oz. 

E.W— 
Hydrochinon 12.5¢ 96 gr. 
Sodium sulphite, dry 50 g 384 gr. 
Sodium carbonate, cryst. 100 g 770 gr. 
Hypo 200 g 3 1/5 oz. 
Ammonia 50 ccm 384 min. 
Water 1000 ccm 16 oz. 

Otsuki & Sudzuki.— 

A. Metoquinone 6g 36 gr. 
Sodium sulphite, dry 30 g 180 gr. 
Water 600 ccm 12 oz. 

B. Hypo 60 g 576 gr. 
Caustic soda 5¢g 48 gr. 
Water 400 ccm 8 oz. 

Mix in equal volumes just before use. 
Bunel.— : 
Amidol 5g 38.5 gr. 
Sodium sulphite, dry 30 g 230 gr. 
Acetone 80 ccm 614 min. 
' Hypo 50 g 385 gr. 
Water 1000 ccm 16 oz. 


88 PHOTOGRAPHIC FACTS AND FORMULAS 


Namias.— 
Metol 
Sodium sulphite, dry 
Hydrochinon 
Caustic soda 
Hypo 
Water 


15g 

30 g 
4.5¢ 

5g 

60 g 
1000 ccm 


lho 
230 gr. 
34 gr. 
38.5 gr. 
460 gr. 
16 oz. 


DEVELOPERS FOR DEEP TANKS FOR COMMERCIAL FINISH- 
ERS.—Eastman Kodak Tank A B C Pyro formulas: 


A. Sodium bisulphite 


Or potassium metabisulphite 


Pyrogallol 
Potassium bromide 
Water to 

B. Sodium sulphite, dry 
Water to 

C. Sodium carbonate, dry 
Water to 


oF 
9g 
60 g 
ue 


1000 ccm 


105 ¢g 


1000 ccm 


75g 


1000 ccm 


140 gr. 
140 er. 
2 oz. 
16 gr. 
32 02 
3¥Y oz. 
32 oz. 
2Y4 oz. 
32 oz. 


Take 5% oz. each of A, B and C and add water to make one 
gallon (162 ccm to make 3785 ccm). Time of development 
about 12 minutes at 65° F. (18° C.). Portrait Super Speed 
film requires about 10 to 15 per cent longer development than 


other film. 
Metol-Pyro tank developer: 

A. Sodium bisulphite 
Metol 
Pyrogallol 
Potassium bromide 
Water to 

B. Sodium sulphite, dry 
Water to 

C. Sodium carbonate, dry 
Water to 


V4 oz. 
Y4 oz. 
1 oz. 
60 gr. 
32 oz. 
5 oz. 
32 oz. 
2¥4 02. 
32 Oz. 


DEVELOPMENT 89 


Take 8 oz. each of A, B and C and add water to make one 
gallon (237 ccm to 3785 ccm). Time of development at 
65° F. (18° C.) from 9 to 12 minutes. This developer can 
be repeatedly used if kept up to its normal strength. For 
strengthening use 2 oz. each of A, B and C to each 8 oz. of 
water (59 ccm to 237 ccm). 

Metol-Hydrochinon tank developer: 


Warm water 4000 ccm 1 gal. 
Metol , 12¢ 170 gr. 
Sodium sulphite, dry 360 g 12 oz. 
Sodium bisulphite Finke V4 oz. 
Hydrochinon Zee 34, OZ. 
Sodium carbonate, dry 45¢ 1¥4 oz. 
Potassium bromide 6g 95 gr. 
Cold water to 16 liters 4 gal. 


Time of development at 65° F. (18° C.) from 10 to 14 
minutes. 
Strengthening solution: 


Water 4000 ccm 1 gal. 
Metol 6g 85 er. 
Sodium sulphite, dry 180 g 6 oz. 
Sodium bisulphite 3.5 2g DOE. 
Hydrochinon 12¢ 170 gr. 
Potassium bromide 2g 45 er. 
Water to 8000 ccm 2 gal. 


To give this stock solution greater keeping quality, the sodium 
carbonate should not be added until the strengthening solution 
is used. For use dissolve % oz. sodium carbonate in 16 oz. 
of the above solution (15 g in 473 ccm), and add to the tank 
Tank developer for Ansco Speedex roll film: 
lgal.tank  10-gal. tank 
A. Warm water (32 oz. 2 gal. 
Metol 22 gr. YZ oz. 


90 PHOTOGRAPHIC FACTS AND FORMULAS 


Sodium sulphite, dry 34 OZ. 7% 02. 
Hydrochinon 90 gr. _ 202. 
Sodium bisulphite V4 oz. 5 oz. 
Potassium bromide 5 gr. 50 gr. 
Sodium carbonate, dry 1 oz. 10 oz. 
Cold water to 2 qt. OY, gal. 
B. Cold water 16 oz. Y, gal. 
Pyrogallol 45 gr. 1 oz. 


Add B to A and develop 15 to 20 minutes at 65° F., accord- 
ing to density desired. For each degree below 65° F., one 
minute should be added to the time of development chosen. 
For each degree above 65° F., one minute should be sub- 
tracted from the chosen development time, provided the bath 
is fairly fresh. 


Renewer : 
Water 32 oz. 2 gal. 
Metol 2 Bt. 4 oz. 
Sodium sulphite, dry 2/5 oz. 4 oz. 
Hydrochinon 45 gr. 1 oz. 
Sodium bisulphite 4 oz. 24 oz. 
Sodium carbonate, dry 2/5 oz. 4 oz. 


The renewer is added from time to time to keep the developer 
even with the top of the tank and at the same time to freshen 
up the solution. A fresh bath should, however, be mixed 
up every two or three weeks at least, according to the number 
of rolls developed in the old solution. 


Developers 


AcroLt.—The Eastman name for amidol, which see. 

ApuroL.—This is either bromhydrochinon (Schering) or 
chlorhydrochinon (Hauff), gives softer negatives than 
hydrochinon, and is less affected by temperature: 


A. Sodium sulphite, dry Ware pes 2 oz. 
Adurol ; 16.6 g 128 gr. 
Water 1000 ccm 16 oz. 

B. Sodium carbonate, cryst. 350 g 534 oz. 
Water 1000 ccm 16 oz. 

Mix 3 parts A with 2 parts B. 

A. Adurol. 20 g 154 gr. 
Potassium metabisulphite 20 g 154 gr. 
Water 1000 ccm 16 oz. 

B. Caustic soda 75g 576 gr. 
Potassium bromide 2g 15 gr. 
Water 1000 ccm 16 oz. 

Mix in equal volumes. 

A. Adurol 20 g 154 gr. 
Sodium sulphite, dry 80 g 615 gr. 
Water 1000 ccm 16 oz. 

B. Potassium carbonate 125 ¢ Pay e 
Water 1000 ccm 16 oz. 


For studio and instantaneous work mix in equal volumes. 
For time exposures and landscape work mix equal volumes 
A, B, and water. 


AmipoL.—A stable amidol developer (Namias) : 


Sodium sulphite, dry 25g 192 gr. 
Amidol 5g 38Y gr. 


91 


92 PHOTOGRAPHIC FACTS AND FORMULAS 


Metol lg 
Potassium bromide 2g 
Water 1000 ccm 


The metol exerts a protective action for the amidol. 
Desalme has suggested as a preservative stannous tartrate, 


which is made as follows: 


Stannous chloride 50 g 
Tartaric acid 70g 
Boiling water 350 ccm 
To this add the following solution: 
Sodium carbonate, dry 55g 
Warm water 300 ccm 


384 gr. 
538 gr. 
5Y4 oz. 


422 er. 
5 oz. 


Filter the mixture and make up to 1000 ccm (16 0z.). Make 


the amidol developer stock as follows: 


Amidol I5¢g 
Sodium sulphite, dry 552g 
Stannous tartrate, as above 100ccm 
Water 1000 ccm 


Lise 
422 gr. 
768 min. 
16 oz. 


For use dilute with 2 parts of water and add 3 per cent of 
sodium bisulphite lye. This stannous tartrate solution may 
also be successfully used with other developing agents. An- 
other method of making the stannous tartrate solution is as 


follows: 
Stannous chloride 10g 
Tartaric acid IS g 
Water 50 ccm 
And add: 
Sodium carbonate Paws 
Water 250 ccm 


77 gr. 
115 gr. 
loz. 


192 gr. 
5 oz. 


Filter and make up the bulk to 1000 ccm (16 oz.). 
Glycollic and lactic acids have also been recommended as 


preservatives and act well: 


DEVELOPERS 93 


Sodium sulphite, dry 31.25 ¢g Y, o2z. 
Amidol 6.3 g 48 gr. 
Potassium bromide 14g 10 gr. 
Glycollic acid 1.4 ccm 10 min. 
Water 1000 ccm 16 oz. 
Ors 
Sodium sulphite, dry 30 g 230 gr. 
Amidol 5g 38.5 gr. 
Lactic acid Ss CCihl 40 min. 
Water 1000 ccm 16 oz. 
Alkaline amidol (Valenta). 
Sodium sulphite, dry I5¢g 115 gr. 
Amidol 5g 38% gr. 
Caustic soda lg 7.7 gr. 
Water 1000 ccm 16 oz. 


This keeps quite clear during development and does not stain. 
Amidol is sold by the Eastman Kodak Co. under the name 
Acrol. 
AmipoL-Pyro.—The following is recommended as having 
all the good properties of amidol and yet giving an image of 
the same colour as pyro: 


Potassium metabisulphite Lice 8 gr. 
Sodium sulphite, dry 42 ¢ 336 gr. 
Amidol 5g AO gr. 
Pyrogallol LIES 16 gr. 
Potassium bromide lg 8 gr. 
Water 1000 ccm 16 oz. 
To this is added just before use: 
Caustic soda lg 8 gr. 
Water 1000 ccm 16 oz. 


This can be used for plates and papers without staining. The 
Watkins factor is 10. 


94 PHOTOGRAPHIC FACTS AND FORMULAS 


DioceEN.—Generally used in one solution: 


Sodium sulphite, dry 150 ¢ 202.) a/2.8% 
Diogen 75¢ 10z., 196 gr. 
Potassium carbonate 375 g 6 oz. 
Water 1000 ccm 16 oz. 


Mix 1 part with 4 parts water. 
EpINnoL.—One solution: 


Potassium metabisulphite 300g +402z., 384 gr. 

Water 500 ccm 8 oz. 
Dissolve and add: 

Edinol 100g loz., 318 gr. 
Then add: 

Caustic potash 220g 30z., 249 gr. 

Water 1000 ccm 16 oz. 


Mix 1 part with 10 to 20 parts water. 
One solution with carbonate: 


Sodium sulphite, dry 50 g 384 gr. 
Edinol | 50 g 384 gr. 
Sodium carbonate, dry 25 ¢ 96 gr. 
Water 1000 ccm 16 oz. 


Mix 1 part with 5 to 10 parts water. The sodium carbonate 
may be replaced by potassium carbonate 15g (ll15gr.), 
when the developer acts more rapidly. Gives very clean 
negatives. 


Two solution: 


A. Edinol 10¢g 47. gt: 
Sodium sulphite, dry 100 g 770 gr. 
Water 1000 ccm 16 oz. 

B. Sodium carbonate, dry 5 per cent solution 
or Potassium carbonate 5 per cent solution 


Mix in equal volumes. The potash works more rapidly and 
gives denser negatives. 


DEVELOPERS 95 


Stock solution for Hammer Plates: 


Sodium sulphite 125 ¢ 214 02. 
Edinol 10g 96 gr. 
Sodium carbonate 50 g 1 oz. 
Water 1000 ccm 20 oz. 


For use mix with an equal volume of water. 
EIKONOGEN.—A slow acting soft developer: 


A. Sodium sulphite, dry 67 g 514 gr. 
Eikonogen 16.6 g 128 gr. 
Water 1000 ccm 16 oz. 

B. Sodium carbonate, dry 75g 576 gr. 
Water 1000 ccm 16 oz. 


Mix 3 parts A with 1 part B. A more rapid acting developer 
can be made by replacing the soda by an equivalent weight of 
potassium carbonate, namely 98 g (752 gr.). 


One solution: 


Sodium sulphite, dry 60 g 460 er. 
Potassium carbonate 50 g 384 gr. 
Eikonogen 30 g 230 gr. 
Boiling water 1000 ccm 16 oz. 


Keeps well. For use mix with an equal volume of water. 

Eton.—Another name for Metol, under which heading the 
Eastman Elon formulas may be found. 

Ferrous OxALATE.—The use of this developer has been 
completely abandoned, mainly because plates are actually 
slower when developed with it than with the organic devel- 
opers, and also because of the deposition of calcium oxalate 
and basic iron salts in the gelatine film. On the other hand, 
it has the great advantage of giving an image composed of 
nothing but pure silver which is a neutral colour, that is, 
without selective absorption, and is, therefore, valuable in 
certain photochemical investigations. Ferrous oxalate is a 
yellow stable powder, insoluble in water, which can be pre- 


96 PHOTOGRAPHIC FACTS AND FORMULAS 


pared by mixing ferrous sulphate with oxalic acid or a soluble 
oxalate, as follows: 

Ferrous sulphate 278 parts 

Water 500 parts 


Dissolve and add: 

Potassium oxalate, neutral 184 parts 

Water 500 parts 
Mix the two solutions, filter and wash the precipitate with 
four or five lots of distilled water, and dry. The result 
should be 180 parts of ferrous oxalate. Oxalic acid 126 parts 
may be used instead of the potassium salt. Ferrous oxalate 
is soluble in excess of neutral potassium oxalate, or other 
alkaline oxalate. It is obvious that the developer may be pre- 
pared in two ways: either by dissolving the dry salt in oxalate 
solution, or by adding ferrous sulphate solution to excess of 
an alkaline oxalate, when it will remain in solution. Potas- 
sium oxalate is used in preference to the corresponding 
ammonium and sodium oxalates, because it is more soluble. 
Consequently, it will dissolve more of the ferrous oxalate, 
which is the active agent in development. The strongest 
developer can be made as follows: 


Potassium oxalate 500 g 8 oz. 

Water 1000 ccm 16 oz. 
Boil and add: 

Ferrous oxalate, dry 100 g 1 3/5 oz. 


Allow to cool slightly and immediately bottle. This practi- 
cally forms a saturated solution of ferrous oxalate. This 
method is not so convenient as using separate solutions, for 
which the following stock solutions are required: 


A. Ferrous sulphate 330 g 5% oz. 
Water 1000 ccm 16 oz. 


Sulphuric acid 1 ccm 7 min. 


DEVELOPERS Th 


The iron salt should preferably be pure, and, if covered at all 
with whitish or yellowish powder, a little excess should be 
allowed in weighing out. The crystals are to be placed in a 
flask, covered with water, well stirred, and the water poured 
off. Then the acid should be added to about three-fourths of 
the water, the salt dissolved, and the bulk made up with the 
remainder of the water. As this solution readily oxidises on 
exposure to the air, it is better to keep it in small bottles, and 
fill them right up to the cork: 


B. Potassium oxalate 330 g 5% oz. 
Hot water 1000 ccm 16 oz. 


For use add 1 part of A to 4 parts of B. The usual strength 
is 1: 3, but this is apt to deposit the insoluble ferrous oxalate. 
If the order of mixing is reversed, the insoluble iron salt is 
at once precipitated, as there is no excess of oxalate to 
dissolve it. Wiauth this developer the image appears in from 
10 to 30 seconds and is complete in 2 to 5 minutes. Potassium 
bromide, may, of course, be added as restrainer. As an 
accelerator a few drops of weak hypo solution may be used, 
about 10 drops of a 1: 200 solution to 100 ccm or 4 drops to 
the ounce; but this is apt to give fog. 

Modifications have been suggested mainly for use with 
gelatino-chloride lantern plates, and, by suitably prolonging 
the exposure and modifying the developer, any tone can be 
obtained from black to red. For black or purple tones the 
following may be used: 


A. Potassium citrate, neutral 450 g 7 Oz 
Potassium oxalate, neutral Lig 784 gr. 
Water 1000 ccm 16 oz. 

B. Ferrous sulphate 200 g RS aya: 
Water 1000 ccm 16 oz. 


Mix in equal parts. 


98 PHOTOGRAPHIC FACTS AND FORMULAS 


I. Potassium oxalate 125 ¢g 2 oz. 
Potassium citrate 42 ¢ YY o7z. 
Water 1000 ccm 16 oz. 

This gives cold tones. 

II. Citric acid 333 g 54. /Si0z: 
Ammonium carbonate 250 g 4 oz. 
Water 1000 ccm 16 oz. 

Gives warm tones. 

III. Citric acid 500 g 8 oz. 
Ammonium carbonate 166 g 22/3 02. 
Water 1000 ccm 16 oz. 

Gives extra warm tones. 

IV. Ferrous sulphate 333 g 5 1/3 oz. 
Sulphuric acid 12.5 ccm 96 min. 
Water 1000 ccm 16 oz. 


For use add 1 part of IV to 3 parts of I, II, or III. Another 
modification is: 


Citric acid 250 g 4 oz. 
Magnesium carbonate 157 g 24 02. 
Water 1000 ccm 16 oz. 


This can be used instead of I, II, or III given above. 

Should any calcium oxalate be precipitated in the gelatine, 
a weak hydrochloric acid bath, about 1 per cent, will remove 
the precipitate. 

Gtycin.—This is a slow-working very clean developer 
giving images of a neutral grey colour, and is very suitable for 
stand development. 

Glycin paste (Hibl). — 


Sodium sulphite, dry 125 ¢ 1% oz. 
Warm water 400 ccm 4 oz. 


Glycin 100 g 1 oz. 


DEVELOPERS oo 


Mix well and add gradually: 


Potassium carbonate 500 g Sr0z: 
Water to make 750 ccm 7% 02. 


Carbonic acid is given off and a thin cream formed, which 
must be well shaken and mixed with 12 times its volume of 
water before use. 

Glycin-soda.— 


Glycin I5¢ Lipitor. 
Sodium sulphite, dry a7 Dig 288 gr. 
Sodium carbonate, dry bag 422 gr. 
Water 1000 ccm 16 oz. 
Glycin-potash (Hubl).— , 
Potassium metabisulphite 175¢ 20z., 384 gr. 
Caustic potash 175¢ 20z., 384 gr. 
Glycin 120 g 922 gr. 
Water 1000 ccm 16 oz. 


Mix 1 part with 25 parts water. 
HyprocHINON.—One solution: 


Sodium sulphite, dry 37.52 288 gr. 

Hydrochinon 10g 77 gr. 

Sodium carbonate, cryst. 150 g 1152 gr. 

Hot water 1000 ccm 16 oz. 
Two solution: 

A. Hydrochinon 25¢ Oat: 
Sodium sulphite, dry 50 g 384 gr. 
Water 1000 ccm 16 oz. 

B. Potassium carbonate 10 per cent solution 


Mix 2 parts A with 1 part B. 
One solution: 


Hydrochinon tie TiS er: 
Sodium sulphite, dry 150g L132 or 
Formaldehyde 20 ccm 154 min. 


Water 1000 ccm 16 oz. 


100 PHOTOGRAPHIC FACTS AND FORMULAS 


Especially suitable for black and white line work. The fol- 
lowing also is excellent for the same purpose: 


A. Hydrochinon 8.5 g 65 gr. 
Potassium metabisulphite 8.5 g 65 gr. 
Potassium bromide 2.0 ¢g 16 gr. 
Water 1000 ccm 16 oz. 

B. Caustic potash l7 g Lolo 
Water 1000 ccm 16 oz. 


Mix in equal parts. 

For very fine grained images, add 50 to 300g (384 gr. to 
5% 0z.) of ammonium chloride to every liter (160z.) of 
normal hydrochinon developer. 

Rapid acting, soft-working developer (Lainer) : 


A. Hydrochinon 10g 77 gr. 
Sodium sulphite, dry 20 g 154 gr. 
Potassium ferrocyanide 120 ¢ 922 or. 
Water 1000 ccm Se 16 OZ, 

B. Caustic potash 50 g 384 gr. 
Water 1000 ccm 16 oz. 


For use mix 10 parts A with 1 part B. Development will be 
completed in about one minute. If caustic soda is used, the 
ferrocyanide may be reduced to one-fifth. For general use 
it is better to mix the developer with an equal volume of 
water. 

One solution developer (Lainer) : 


Sodium sulphite, dry 75g 576 gr. 
Hydrochinon 50 g 384 gr. 
Potassium ferrocyanide 175 ¢g 1344 gr. 
Caustic potash 165 g 1267 gr. 
Water 1000 ccm 16 oz. 


For use dilute with 4 parts of water. 
For Eastman Motion Picture Film, Negative and Pos- 
itive.— 


DEVELOPERS 101 


Hydrochinon 390 g 13 oz. 
Sodium sulphite, dry 2000 g 4 Ib. 
Sodium carbonate, dry 2000 g 4 Ib. 
Potassium bromide 90 g 3 OZ. 
Water 40 litres 1280 oz. 


Temperature 65° to 68° F. For film developed on drum add 
to above 45g (1% oz.) potassium bromide and develop at 
Gee i, 

Cramer’s Contrast Developer for Line Work.— 


A. Hydrochinon 45 ¢ 1Y oz. 
Sodium sulphite, dry 30 g Loz: 
Sulphuric acid 4 ccm 60 min. 
Water 1000 ccm OLI0z. 

B. Sodium carbonate, dry 30 g 1 oz. 
Potassium carbonate 90 g 3 02. 
Potassium bromide 8g 120 gr. 
Sodium sulphite, dry 90 g 3:02. 
Water 1000 ccm 32 02. 


For use mix in equal volumes. Develop for 6 to 10 minutes. 
Temperature 21° C. (70° F.). This may also be used for 
X-ray and lantern plates. 

KopELon.—Paramidophenol hydrochloride is sold by the 
Eastman Kodak Co. under this name, especially for use with 
developing papers, under which heading formulas may be 
found. 

Meto.t.—A very rapid developer, rarely used alone, but 
generally in combination with hydrochinon or pyrogallol. 
Also marketed by the Eastman Kodak Co. under the name 
Elon. Motol is another synonym. 


Metol-potash.— 
A. Metol 10g Liat. 
Sodium sulphite, dry 50 ¢ 384 gr. 


Water 1000 ccm 16 oz. 


102 PHOTOGRAPHIC FACTS AND FORMULAS 


B. Potassium carbonate 100 g 1 oz. 
Water 1000 ccm 10 oz. 
Mix 3 parts A with 1 part B. 
Metol-soda.—Replace the potassium carbonate in B by 
Sodium carbonate, dry 50 g 384 gr. 
For use mix A and B in equal volumes. 
One solution: 


Metol I5¢ 115 or. soe 
Sodium sulphite, dry 60 g 460 gr. 115 
Sodium carbonate, dry 75g 576 gr. 
Potassium bromide Lg It her 
Water 1000 ccm 16 oz. 


For studio work mix with an equal volume of water. For 
landscape work mix I part with 2 parts water. 

Metol poisoning (Beers)—The hands should be dipped 
into a saturated solution of paraffine in gasoline (petrol) 
before using metol. Less severe forms of the trouble can be 
treated with: 


Carbolic acid 2Zlg 160 gr. 
Powdered calamine Ses 240 ger. 
Zinc oxide 63 g 480 er. 
Glycerine 65 ccm 1 oz. 
Lime water 250 ccm 4 oz. 
Rose water to 1000 ccm 16 oz. 


Rub the zinc and calamine into a smooth paste with the 
glycerine, and add the carbolic acid and the rest of the 
waters. This may be applied during the day. The following 
should be applied at night: 


Salicylic acid lg 15 gr. 
Boric acid 4¢ 60 gr. 
Starch powder 8g 120 gr. 
Zinc oxide 4¢ 60 gr. 


Petrolatum 32g 1 oz. 


DEVELOPERS / 103 


Flexible collodion should be applied to all cracks during the 
day. 
Metol-hydrochinon (Cramer ).— 


A. Metol DY Ad 30 gr. 
Hydrochinon 6g 90 gr. 
Sodium sulphite, dry 30 g 1 oz. 
Water 750 ccm 25 oz. 

B. Sodium carbonate, dry I5¢g Y oz. 
Water _ = 750 ccm 25/02, 


For use mix in equal voluthes. 
Ansco Metol-Hydrochinon.— 


Metol 2 1.56 ¢ 48 er. 
Hydrochinon ~ 0.78 g 24 er. 
Sodum sulphite, dry 9g 280 gr. 
Sodium carbonate, dry 6g 180 gr. 
Potassium bromide ~ 0.39 g 12 gr. 
Water 1000 ccm 64 oz. 


. Time, 5 or 6 minutes at 18° C. (65° F.). 
eead. 0). aan Motion Picture Film, Negatwe & Posi- 


le 


tive.— 


> » 


Elon tae 1ST 12 g 180 gr. 
Sodium stilphite, dry 1590 g 8 ibe aoz. 
Hydrochinon 240 ¢ 8 02. 
Potassium bromide 362 hoz.,.63 gr. 
_ Sodium carbonate, dry 750 g Libi?o2: 
Citric acid 28 g 400 gr. 
Potassium metabisulphite 60 g pete cee 
Water 40 liters | 1280 oz. 


iemperarure 69° F. (18° C.). 
Eastman Portrait & Commercial Films—Metol- hydro- 
chinon tank formula.— 
Elon (metol) 0.8 ¢ 170 er. 
Sodium sulphite, dry 23,0 2 12 oz. 


4 


P Re : 


104 PHOTOGRAPHIC FACTS AND FORMULAS 


Sodium bisulphite 0.5 g \4 OZ. 
Hydrochinon 15g 34 OZ. 
Sodium carbonate, dry 3g 14 oz. 
Potassium bromide 0.4 ¢ 95 gr. 
Water to 1000 ccm S1207. 


Temperature 18° C. (65° F.). Development from 10 to 14 
minutes. The following strengthening solution may be used 
to keep the volume and strength up to standard: 


Elon (metol) 0.75 g 85 gr. 
Sodium sulphite, dry 2315, 6 oz. 
Sodium bisulphite Os ie 
Hydrochinon hog 170 gr. 
Potassium bromide 0.4¢ 45 ger. 
Water to 1000 ccm 256 oz. 


To give this stock solution greater keeping quality, the sodium 
carbonate is not added until the strengthening solution is 
used. For use dissolve 1 part of sodium carbonate, dry, in 
32 parts of the above solution. 

Standard Postcard Plates.— 


Elon (metol) Se YY oz. 
Sodium sulphite, dry 31.2592 4 oz. 
Hydrochinon 7.82 Loz 
Sodium carbonate, dry 47g 6 oz. 
Potassium bromide 195 g V4 oz. 
Water 1000 ccm 128 oz. 


For use mix with an equal volume of water. 
Stanley Plates—For these plates the following metol- 
hydrochinon developer is recommended : 


Elon (metol) 3.9¢ 30 gr. 
Sodium sulphite, dry 31.25 ¢ 4 oz. 
Hydrochinon 3.9 ¢ 30 gr. 
Sodium carbonate, dry 15.625 g Y4 oz. 


Water 1000 ccm 16 oz. 


For use mix 1 part with 7 parts water, and use at 65° F. 
Seed Graflex Plates—Contrast Developer— 
A. 


B. 


For use mix 3 parts A, 1 part B, 2 parts water. 


DEVELOPERS 


Elon (metol) 3.9¢g 
Sodium sulphite, dry 47g 
Hydrochinon 7.8¢ 
Potassium bromide 6.5 g 
Water 1000 ccm 
Sodium carbonate, dry ahV ae 
Water 1000 ccm 


Metol-Hydrochinon-Pyro.— 


A. Elon (metol) 2.2/2 
Sodium sulphite, dry BN rapel tng 
Hydrochinon 8.5 ¢ 
Sodium carbonate, dry be oe 
Water 1000 ccm 

B. Sodium bisulphite (or 


potassium metabisulphite) 9.2¢ 


Potassium bromide 2.6¢ 
Pyrogallol 62.5 ¢ 
Water 1000 ccm 


For use mix 8 parts A and 1 part B. 
Seed Platcs.— 


A. Elon (metol) 4¢ 
Sodium sulphite, dry 31.25 ¢ 
Hydrochinon 4g 
Potassium bromide 2g 
Water 1000 ccm 

B. Sodium carbonate, dry 94 ¢ 
Water 1000 ccm 


60 gr. 
LY oz. 
120 gr. 

50 gr. 

32.02. 

5 oz. 

16 oz. 


35 gr. 
1 oz. 
130 gr. 
800 gr. 
aZi07 


70 gr. 
20 gr. 

1 oz. 
16 oz. 


105 


For tray developer, use A 4 parts, B 1 part, water 4 parts. 


106 PHOTOGRAPHIC FACTS AND FORMULAS 


Eastman X-Ray Fiulm.— 


Elon (metol) 2/72 40 gr. 
Sodium sulphite, dry 120 g 4 oz. 
Hydrochinon ive 160 gr. 
Sodium carbonate, dry 60 g 202. 
Potassium bromide 2.1¢ 32 gr. 
Water 1200 ccm 40 oz. 
The above is for tray development ; for tank, use: 
Elon (metol) 42¢ 1oz., 240 ger. 
Sodium sulphite, dry 2040 g 68 oz. 
Hydrochinon 185¢ 60z., 96 gr. 
Sodium carbonate, dry 1020 g 34 oz. 
Potassium bromide 36 g 550 gr. 
Water to 22000 ccm 6 gal. 

Hammer Postal Plate.-—Stock solutions: 

1. Metol 2/¢ 165 gr. 
Hydrochinon 10g 14 oz. 
Sodium sulphite 38 g 6 oz. 
Water 1000 ccm 128 oz. 

2. Sodium carbonate ev ie 10 oz. 
Water 1000 ccm 128 oz. 


For use mix equal parts of Nos. 1 and 2. 
One solution developer: 


Metol 0.15 g 22¥4 gr. 
Hydrochinon 0.30 g 45 er. 
Sodium sulphite I2¢g 34 OZ. 
Sodium carbonate 4¢g Y oz. 
Potassium bromide 04¢ 6 gr. 
Water 1000 ccm 32 Gz, 


For use mix with an equal volume of water. 


Rexo Film.—Dissolve the chemicals in the following order: 
Metol hice 20 gr. 
Sodium sulphite, dry l4g YZ oz. 


DEVELOPERS 
Hydrochinon 4¢g 60 gr. 
Sodium carbonate, dry 2Zlg 34, OZ. 
Potassium bromide lg 15 gr. 
Water 1150 ccm 40 oz. 


107 


Nro.t.—This is a fine, white, crystalline powder, insoluble 
in water except in the presence of caustic alkali, which should 
be very pure, so that the manufacturers recommend only the 
use of Hauff alkali, which may be obtained either in solid 
form or in solution, in connection with this developer. The 


alkaline solution is prepared as follows: 
Hauff alkali (caustic soda) 400 ccm 2 OZ. 
Water 1000 ccm Mande 
The developing solution is compounded as follows. 
tray development; time, three to five minutes: 


Water 1000 ccm 16 oz. 
Sodium sulphite, anhydrous 5g 40 ger. 
Neol lye solution, as above 20ccm V7 S'0z. 
Neol 4¢ “ey Uieaig: 


For 


nod vy 


In case of over-exposure 10 to 20 drops of 10 per cent potas- 


sium bromide solution may be added. 
For tank development, 15 to 20 minutes: 


Water 100 liters 25 gal. 
Sodium sulphite, anhydrous 300¢ 10 oz. 
Neol lye solution 1200 g 40 oz. 
Neol 200 g 634 oz. 
Potassium bromide, 10% sol. 15 ccm Vy oz. 


14% 
44. 


% 


Neol is claimed to work free from fog and therefore to 


be excellent for underexposed negatives. 


OrtoLt.—A molecular compound of two molecules of metol 


with one of hydrochinon: 
A. Potassium metabisulphite 7.52 SS /eons 
Ortol I5¢ 115 ger. 
Water 1000 ccm 16 oz. 


108 PHOTOGRAPHIC FACTS AND FORMULAS 


B. Sodium carbonate, dry 60 g 460 er. 
Sodium sulphite, dry 90 g 690 er. 
Potassium bromide lig TiS er 
Hypo O5¢ 3.8 gr. 
Water 1000 ccm 16 oz. 


The same weight of potassium carbonate may be used instead 
of the soda. Mix 1 part A, 1 part B, and 1 part water; for 
a more rapid developer mix A and B in equal volumes. 


Stock solutions for Hammer plates: 


1. Ortol 21g 160 gr. 
Water 1000 ccm 16 oz. 
2. Sodium carbonate 3lg 240 er. 
Sodium sulphite Ieper 2 120 gr. 
Water 1000 ccm 16 oz. 
For use take: 
No. 1 solution 125 ccm 1 oz. 
No. 2 solution 125 ccm 1 oz. 
Water 750 ccm 6 oz. 
PARAMIDOPHENOL.—One solution: 
Paramidophenol hydrochloride 4g Ser: 
Sodium sulphite, dry 40 g 310 gr. 
Sodium carbonate, dry 40 ¢ J10gE 
Water 1000 ccm 16 oz. 
Ready for use. Does not keep so well as in separate solutions. 
A. Paramidophenol hydrochloride 20g 154 gr. 
Water 1000 ccm 16 oz. 
B. Sodium sulphite, dry 60 g 460 er. 
Potassium carbonate 120 g 920 gr. 
Water 2000 ccm 32 Oz. 


Mix 1 part A with 2 parts B. More suitable for papers and 
transparencies than negatives. 
One solution, similar to rodinal (Ermen) : 
Water 625 ccm 11 oz. 


DEVELOPERS 109 


Boil, allow to cool for 5 minutes, and add a few crystals of 
potassium metabisulphite; then add: 


Paramidophenol hydrochloride 50g 385 gr. 

Potassium metabisulphite TOO pe Oz nl 2 Ore 
Stir until dissolved. Then make a solution of : 

Caustic soda 215 ¢g 3Y4 02. 

Water 500 ccm 834 Oz. 


and add with constant stirring about 340 to 350 ccm (6 oz.) 
to the paramidophenol solution. At first a precipitate of the 
paramidophenol base is formed, but, as more caustic soda 
is added, this dissolves. Enough soda solution should be 
added to nearly dissolve the precipitate; then add: 

Water to make 1000 ccm 16 oz. 
Bottle and allow to cool. Should any paramidophenol crys- 
tallise out, more soda must be added to nearly dissolve it. It 
is very important to leave some undissolved. For use mix 1 
part with 10 parts water with some bromide for plates, and 
with 40 parts water for papers. 

Liquid developers consisting of paramidophenol and an 
alkali are marketed under such names as rodinal, azol, activol, 
citol, paranol, paramol, certinal, kalogen, etc. 

PARAPHENYLENDIAMINE, for fine-grained images (Lumi- 
ére & Seyewetz).—The following gives a finer grain image 
than most developers: 


Paraphenylendiamine 10 ¢ TTS oe 
Sodium sulphite, dry 60 g 460 er. 
Water 1000 ccm 16 oz. 
PyROCATECHIN OR Kacuin.—A\lso called Elconal. 
A. Pyrocatechin lg 8 gr. 
Water 1000 ccm 16 oz. 
B. Potassium carbonate 200 g 1 oz. 
Water 1000 ccm OZ 


For use mix 10 parts A with 1 part B. Gives brownish 


110 PHOTOGRAPHIC FACTS AND FORMULAS 


images, suitable for transparencies. The developer can only 
be used once, as it spoils rapidly. 
P yrocatechin-Potash._— 


A. Pyrocatechin 200g 30z., 224 gr. 
Sodium sulphite, dry 400 g 7 OZ. 
Water 1000 ccm 16 oz. 

B. Potassium carbonate 120 ¢ 922 gr. 
Water 1000 ccm 16 oz. 


For use mix in equal parts. 
One solution: 


Potassium metabisulphite 100 g 2 Oz. 
Potassium carbonate 150 g 3 07; 
Water 400 ccm 8 oz. 


Mix in a mortar and add: 

Pyrocatechin 350 g 7 OZ. 
This forms a thick cream which must be stored in well-corked 
bottles. Mix 1 part with 20 parts of water. 


Rapid one-solution developer (Ellon) — 


Sodium sulphite, dry 250 g 4 oz. 
Caustic soda 35 g 269 gr. 
Pyrocatechin 50 g 384 gr. 
Water \ 1000 ccm 16 oz. 


Mix 1 part with 15 parts of water. 
Two-solution (V ogel).— 


A. Sodium sulphite, dry 50 g 384 gr. 
Pyrocatechin 20 g 154 gr. 
Water 1000 ccm 16 oz. 

B. Caustic soda l4¢g 108 gr. 
Water 1000 ccm 16 oz. 


Mix 1 part A, 1 part B with 4 parts water. 


Pyrocatechin-acetone (Hanneke).— 
Pyrocatechin ; 10g 7 gr. 


DEVELOPERS 111 


Sodium sulphite, dry 12g 92 gr. 
Water 1000 ccm 16 oz. 
Mix just before use 12 parts with 1 part acetone. 
PyROGALLOL.—Pyro-ammonia was once the favorite de- 
veloper, but is rarely used now on account of its variability, 
due to the evaporation of the ammonia: 


A. Sodium sulphite, dry 50 g 384 gr. 
Sulphuric acid 6 drops 3 drops 
Pyrogallol 14 ¢ 107.5 gr. 
Water 500 ccm 8 oz. 

B. Potassium bromide 10 per cent solution 

C. Ammonia, sp. gr. 0.91 200 ccm 4 oz. 
Water 1000 ccm 20 oz. 


For use mix 5 parts A, 1 part B, 5 parts C, and 50 parts water. 
Pyro-glycerine (Edwards )— 


A. Pyrogallol 40 g 1 oz. 
Glycerine 40 ccm 1 oz. 
Denatured alcohol 

(methylated spirit) 250 ccm 6% oz. 

B. Potassium bromide I5 ¢g 65 gr. 
Ammonia 40 ccm 1 oz. 
Glycerine 40 ccm 1 oz. 
Water 250 ccm 6% oz. 


For use mix 1 part A, 1 part B, and 30 parts water. 
For great contrasts, suitable for black and white line work 
or photomechanical or process plates (Mawson) : 


A. Pyrogallol afi 54 ger. 
Ammonium bromide 7g 54 gr. 
Potassium metabisulphite 72 54 gr. 
Water 1000 ccm 16 oz. 

B. Ammonia, sp. gr.0.91 ~© 21ccm 160 min. 
Water 1000 ccm 16 oz. 


For use, mix in equal volumes. 


112 PHOTOGRAPHIC FACTS AND FORMULAS 


Pyro-Soda.— 

A. Sodium sulphite, dry 50 g Loz 
Sulphuric acid 6 ccm 3 drops 
Pyrogallol l4g 122 gr. 
Water 500 ccm 10 oz. 

B. Sodium carbonate, cryst. 50 g 1 oz. 
Water 500 ccm 10 oz. 


For use mix in equal volumes. 

The “B. J.” Pyro-Soda—Specially recommended by the 
British Journal of Photography. It keeps well and does not 
Sigit we 


A. Pyrogallol 16.6 g 1 oz. 
Sodium sulphite, dry 66g 4 oz. 
Potassium metabisulphite 16.6 g 1 oz. 
Hot water 1000 ccm 60 oz. 


Mix the sulphite and metabisulphite dry, and add to half the 
water ; boil for one minute, add the pyro, then the remainder 
of the water, and cool. 
B. Sodium carbonate, cryst. 200 g 12 oz. 
Water 1000 ccm 60 oz. 
For use mix 1 part A, 1 part B and 2 parts water. 
Hurter & Driffield Standard Developer—Recommended 
for plate testing: 


Pyrogallol 8 parts 
Sodium carbonate, cryst. 40 parts 
Sodium sulphite, cryst. 40 parts 
Water 1000 parts 


Pyro-Caustic (Valenta).—A very rapid stainless developer, 
acting very much like metol: 
A. Sodium sulphite, dry 80 ¢ 615 gr. 
Pyrogallol Zoe 192 gr. 
Water 1000 ccm 16 oz. 


DEVELOPERS 
B. Caustic potash 1l.5¢ 88.3 gr. 
(or Caustic soda) 8.5 g 65.3 gr. 
Water 1000 ccm 16 oz. 


For use mix 1 part A, 1 part B and 1 part water. 
Pyro-Acetone (Lumiere). — 


A. Pyrogallol 100 g 768 gr. 
Sodium sulphite, dry 200 g 1536 gr. 
Water 1000 ccm 16 oz. 


113 


Potassium metabisulphite must not be used, nor must acid be 
added. For use mix A 8 parts, acetone 8 parts and water 


100 parts. 
Pyro-Potash (Beach). — 

A. Pyrogallol 100 g 1 oz. 
Sodium sulphite, dry 200 g Z Oz. 
Sulphurous acid 400 ccm 4 oz. 
Hot water 500 ccm D1OZ. 

Dissolve the sulphite; when cold add the acid, and then the 
pyro. 

B. Potassium carbonate 350 3 OZ. 
Sodium sulphite, dry lllg 1 oz. 
Hot water : 1000 ccm 10 oz. 


For use mix 1 part A, 2 parts B and 16 parts water. 
Cramer's Pyro Tank Developer.— 


Sodium bisulphite 19.5 g 24 02. 

Sodium sulphite, dry 19.5¢ 24 02. 

Hot water 500 ccm 64 oz. 
Dissolve and boil for 5 minutes; then add: 

Pyrogallol L5:5'¢, 2 oz. 

Sodium carbonate, dry L/e 3 oz. 

Cold water 500 ccm 64 oz. 


To keep up to original strength and bulk, add equal volumes 


of the following (A and B) after each day’s working: 


114 PHOTOGRAPHIC FACTS AND FORMULAS 


A. Sodium bisulphite be 24 oz. 
Sodium sulphite, dry 39 g 24 02. 
Hot water 1000 ccm 64 oz. 

Boil for 5 minutes and add when cool: 
Pyrogallol 3l¢g 2 Oz. 

B. Sodium carbonate, dry 62.5 g 4 oz. 
Water 1000 ccm 64 oz. 


Potassium metabisulphite must not be substituted for the 
bisulphite in the above formulas. 


Pyro-soda developer for Cramer plates.— 


A. Sodium bisulphite 5¢g 75 gr. 
Pyrogallol 30 g 1 oz. 
Water 480 ccm 16 oz. 

B. Sodium sulphite, dry 60 g 2 OZ. 
Water 480 ccm 16 oz. 

C. Sodium carbonate, dry 30 g 1 oz. 
Water 480 ccm 16 oz. 

For tray use: 
Solution A 100 ccm 1 oz. 
Solution B 100 ccm 1 oz. 
Solution C 100 ccm 1 oz. 
Water 800 ccm 8 oz. 
For tank use: 
Solution A 250 ccm 2% oz. 
Solution B 350 ccm 3¥Y oz. 
Solution C 250 ccm 24 02. 
Water 5800 ccm 58 oz. 


Temperature 65° F. Time 20 minutes. 
Cramer's Pyro-Acetone.—Stock pyro solution: 


Sodium bisulphite 3.25 g 25 gr. 
Pyrogallol 62.5 g 1 oz. 
Sodium sulphite, dry 182 g 234 Oz. 


Water 1000 ccm 16 oz. 


DEVELOPERS 115 


For tray, use: Stock pyro solution 72 ccm, acetone 24 ccm, 
water 928 ccm; or pyro solution 1 oz., acetone 3 drams, water 
14 oz. 
For tank, use: Pyro solution 21.5 ccm, acetone 12.5 ccm, 
water 1000 ccm; or pyro solution 1% oz., acetone 5 drams, 
water 58 oz. 
Temperature 21° C. (70° F.) Time 30 minutes. 

Ansco Pyro-Soda.— 


1. Potassium metabisulphite 16.3 g 250 gr. 
Sodium sulphite, dry 62.5 ¢ 02. 
Pyrogallol 16.3 g 250 gr. 
Water 1000 ccm S202. 

2. Sodium carbonate, dry 70g 2% 02. 
Water 1000 ccm SPs fay 


For use mix No. 1, 1 part, No. 2, 1 part, water, 2 parts. 
Time of development 5 minutes at 18° C. (65° F.). 
Kodak Film Pack Pyro formula.— 


Pyrogallol Lovie 22 2, 
Sodium sulphite, dry 5g 60 gr. 
Sodium carbonate, dry 6.52 795 gr. 
Water 1000 ccm 27 oz. 


Temperature 18° C. (65° F.). Develop for 20 minutes. 
For Eastman N-C & Autographic Film.— 


A. Pyrogallol 35.7 g 1 oz. 
Sulphuric acid, c. p. 3 ccm 20 min. 
Water 1000 ccm 28 oz. 

B. Sodium sulphite, dry 107 g Zs 
Sodium carbonate, dry (isdie 2 oz. 
Water 1000 ccm 28 oz. 


For use mix 1 part A, 1 part B, 8 parts water. 
For Seed and Stanley Plates——For tray developer : 


116 PHOTOGRAPHIC FACTS AND FORMULAS 


A. Sodium or potassium bisulphite 11.7 g 


Pyrogallol 62.5 ¢ 
Water 1000 ccm 
B. Sodium sulphite, dry 94 ¢ 
Water 1000 ccm 
C. Sodium carbonate, dry 782 
Water 1000 ccm 


For use mix 1 part A, 1 part B, 1 part C, 
For tank developer: 
A. Sodium or potassium bisulphite 9g 


Potassium bromide 0.9 ¢ 
Pyrogallol 62.5 g 
Water 1000 ccm 
B. Sodium sulphite, dry 109 g 
Water 1000 ccm 
C. Sodium carbonate, dry 78g 
Water 1000 ccm 
For use mix 
A solution 36 ccm 
B solution 36 ccm 
C solution 36 ccm 
Water to 1000 ccm 


Temperature 65° F. Develop 15 minutes. 


For Seed 30 and Graflex plates use: 


A solution 47 ccm 
B solution 47 ccm 
C solution 47 ccm 
Water to 1000 ccm 


Temperature 65° F. Develop 15 minutes. 


90 gr. 

loz. 

16 oz. 

LZ oz. 
16 oz. 

1% oz. 
16 oz. 

and 7 parts water. 


70 gr. 
7 gr. 

1 oz. 
16 oz. 
134 oz. 
16 oz. 
1% oz. 
16 oz. 


4Y4 oz. 
4Y4 oz. 
44 oz. 
128 oz. 


6 oz. 
6 oz. 
6 oz. 
128 oz. 


Pyro-Acetone for Hammer Plates—Stock solutions: 


1. Sodium sulphite 1206 
Water 1000 ccm 
Hydrometer test, 75°. 


3 oz. 


23% 02. 


DEVELOPERS 


2. Pyrogallol 
Oxalic acid 
Water 

For use, take: 
No. 1 solution 
No. 2 solution 
Acetone 
Water 


Pyro for Hammer Plates.—Stock solutions: 


1. Sodium sulphite 
Water 
Hydrometer test, 80°. 
2. Sodium carbonate 
Water 
Hydrometer test, 40°. 
3. Potassium metabisulphite 
Pyrogallol 
Water 
For tray take: 
No. 1 solution 
No. 2 solution 
No. 3 solution 
Water (winter ) 
Water (summer ) 
For tank take: 
No. 1 solution 
No. 2 solution 
No. 3 solution 
Water 


1000 ccm 


118 ccm 
59 ccm 
29.5 ccm 
588 ccm 


156 g 
1000 ccm 


782 
1000 ccm 


7.82 
62.5 g 
1000 ccm 


30 ccm 
30 ccm 
30 ccm 
360 ccm 
480 ccm 


43 ccm 
43 ccm 
43 ccm 
870 ccm 


1 oz. 
LOE, 
16 oz. 


1 oz. 
4 oz. 
4 oz. 


Broz: 


24 02. 
16 oz. 


1% oz. 
16 oz. 


60 gr. 
1 oz. 
16 oz. 


Y oz. 
Y oz. 
Y4 oz. 
6 oz. 
8 oz. 


54 oz. 
5¥Y4 oz. 
5Y4 oz. 
1114 oz. 


117 


Bromide potassium, saturated solution, 0.2 ccm, 12 drops. 


Develop 12 minutes at 65° F. 


Rexo Film—Make the following solution: 


118 PHOTOGRAPHIC FACTS AND FORMULAS 


Pyrogallol 28 g 1 oz. 
Oxalic acid 0.5 g 8 gr. 
Water 225 ccm 8 oz. 


For use make the following solutions, Nos. 1 and 2 and mix 
equal parts: 


1. Pyro solution as above 56 ccm 2 02. 
Water 500 ccm 18 oz. 
2. Sodium sulphite, dry 28 g 1 oz. 
Sodium carbonate, dry 14g 4 oz. 
Water 560 ccm 20 oz. 
Tank developer: 
No. 1 solution 56 ccm 2 02. 
No. 2 solution 56 ccm 2 02. 


For 15 minute development add 225 ccm (8 oz.) of water at 
O80? 
For 30 minute development add 560 ccm (20 oz.) of water at 
65008; 

For Wratten Panchromatic Plates.— 


A. Sodium or potassium bisulphite 6g 90 gr. 
Pyrogallol 30 g 1 oz. 
Water 500 ccm 16 oz. 

B. Sodium sulphite, dry 45 ¢ 1¥% oz. 
Water 500 ccm 16 oz. 

C. Sodium carbonate, dry 37.5 g 1% oz. 
Water 500 ccm 16 oz. 


For tray development, mix 1 part A, 1 part B, 1 part C, and 
7 parts water. 

For tank development, mix 1 part A, 1 part B, 1 part C, and 
25 parts water, to which add for every 500 parts, 2 parts of 
1 per cent solution of potassium bromide. 

The times for development for the above tray and tank de- 
velopers are: 


DEVELOPERS 119 


Temperature Tray Tank 
DOE. 12 min. 36 min. 
Gaels 6 min. 18 min. 
80° F. 3 min. 9 min. 


For Standard Plates—The stock solutions are as above. 
To develop Standard Extra, Imperial Portrait, Thermic, or 
Polychrome plates, use 1 part A, 1 part B, 1 part C, 7 parts 
water. For Orthonon plates use the same proportions of A, 
B, C, but 12 parts water. 

For tank developer for Standard Plates, use the same form- 
ula as for Seed plates, except for the Standard Polychrome, 
for which the formula is: 


A solution 54.6 ccm 307. 
B solution 54.6 ccm 3 02. 
C solution 54.6 ccm 3 OZ. 
Water 1000 ccm 55 oz. 


Temperature 65° F. Develop 15 minutes. 


For Eastman Portrait, Commercial, Commercial Ortho & 
Commercial Panchromatic Films—The formulas for the tray 
developer are the same as for the Wratten Panchromatic 
plates. For the tank developer the same formulas are used, 
in the following proportions: 


A solution 43 ccm 5Y4 oz. 

B solution 43 ccm 5Y4 oz. 

C solution 43 ccm 5Y4 oz. 

Water to 1000 ccm 128 oz. 
Pyro-M etol.— 

A. Pyrogallol 8.3 g 64 gr. 
Metol 7g 54 gr. 
Potassium metabisulphite 18.75 g 144 gr. 
Potassium bromide SEN Ass 24 gr. 


Water 1000 ccm 16 oz. 


120 PHOTOGRAPHIC FACTS AND FORMULAS 


B. Sodium carbonate, cryst. 
Water 


Mix in equal volumes. 


156 g 
1000 ccm 


For Hammer Plates.—Stock solutions: 


1. Sodium sulphite 
Water 

2. Sodium carbonate 
Water 

3. Potassium metabisulphite 
Metol 
Pyrogallol 
Potassium bromide 
Water 

For tank take: 

No. 1 solution 
No. 2 solution 
No. 3 solution 
Water 


Develop 10 minutes at 65° F. 


For tray development: 
4. Pyrogallol 
Metol 
Water 
Solution No. 2 as above 
Solution No. 3 as above 
For use take: 
No. 4 solution 
No. 2 solution 
No. 3 solution 
Water 


c& Commercial Films.— 


156 ¢ 
1000 ccm 
782 
1000 ccm 
7.82 
15.6 ¢ 
46.8 g 
3.9 ¢g 
1000 ccm 


41 ccm 


41 ccm ~ 


41 ccm 


877 ccm 


37 g 
46g 
1000 ccm 


100 ccm 
100 ccm 
100 ccm 


800 to 1200 ccm 
Pyro-Metol Tank & Tray Developer for Eastman Portrait 


2¥4 oz. 
16 oz. 


24 oz. 
16 oz. 
1% oz. 
16 oz. 
60 gr. 
4 oz. 
34 02. 
30 gr. 
16 oz. 


5% oz. 
51% oz. 
5% oz. 
112% oz 


1 oz. 
60 gr. 
27 Oz. 


1 oz. 
1 oz. 
1 oz. 
8 to 12 oz. 


DEVELOPERS 121 


A. Sodium bisulphite 15.5¢ V4 oz. 
Elon (metol) Looe V4 oz. 
Pyrogallol 62.5 g haz: 
Potassium bromide 4¢g 60 gr. 
Water 1000 ccm 2:02; 

B. Sodium sulphite, dry 156 ¢g 5 Oz. 
Water 1000 ccm 202: 

C. Sodium carbonate, dry 782 24 oz. 
Water 1000 ccm SPE (aye 


For tank development mix 2 parts each of A, B, and C with 
32 parts water. Temperature 18° C. (65° F.). Develop- 
ment from 9 to 12 minutes. This may be used repeatedly if 
kept up to normal strength. For strengthening add 2 parts 
each of A, B, and C to 8 parts water. For tray development 
mix 2 parts each of A, B, and C with 16 parts water. 


Cramer's Pyro-Metol Developer— 


A. Metol 30 g 1 oz. 
Sodium bisulphite lg 75 gr. 
Pyrogallol 10g YA oz. 
Water 600 ccm 30 oz. 

B. Sodium sulphite, dry 120¢ _ 402. 
Water 600 ccm 30 oz. 

C. Sodium carbonate, dry 120 ¢ 4 oz. 
Water 600 ccm 30 oz. 

For use mix: 
Solution A 10 ccm Y 02. 
Solution B 10 ccm Y4 oz. 
Solution C 10 ccm VY o7z. 
Water 200 to 300ccm = 10 to 15 oz. 


B and C may be mixed together and keep well in one solu- 
tion, which should be diluted for use with from 6 to 10 parts 
of water. | : 


"122 PHOTOGRAPHIC FACTS AND FOR! 


| Tozou.—An Eastman developer. Formula - 


under developing papers. 





Fixing and Clearing 


Fixinc.—The rapidity with which plates, films, and papers 
fix is dependent on the strength of the bath, its temperature, 
and the degree of exhaustion or previous use. A 40 to 45 
per cent solution of hypo is the strongest bath that should be 
used and is the most rapid in action. Plain, alkaline, acid, or 
acid and alum baths may be used. The first two are generally 
used for printing-out papers, and the latter for plates, film, 
and developed papers. In all cases, the temperature should be 
maintained about normal, 18° C. (65° F.). A bath should 
not be used too long, as the more it is used, the greater its 
saturation in silver salts, therefore, the longer it will take to 
fix properly and the greater the chance for the formation of 
insoluble, transparent silver salts which are difficult to wash 
out. 

The easiest way to make a solution is to tie the hypo 
crystals up in a cloth or piece of Canton flannel, and suspend 
in a vessel of hot water. This obviates any necessity for 
filtering the solution. 


Plain bath— 
Hypo 400 g 6¥4 oz. 
Hot water to 1000 ccm 16 oz. 


Alkaline bath—Generally used for silver printing-out 
images : 


Hypo 125 ¢ 2Y4 oz. 
Sodium carbonate, dry eae 4 oz. 
Salt Ag 4 oz. 
Water 1000 ccm 16 oz. 


Sodium sulphite, dry, may be substituted for the carbonate. 
123 


124 PHOTOGRAPHIC FACTS AND FORMULAS 


Acid bath— 
Hypo 150 ¢ 24 oz. 
Potassium metabisulphite 25g Y o7. 
Water 1000 ccm 16 oz. 


This is about the correct strength for papers; for negative 
work the hypo should be increased to 400 g (6% oz.). An 
equally efficient bath is made as follows: 


Hypo 400 g 634 oz. 
Citric acid 30 g 230 gr. 
Sodium sulphite, dry 35 g 270 gr. 
Hot water to 1000 ccm 16 oz. 


Dissolve the hypo in half the water and the acid and sulphite 
in one-fourth, mix the solutions and make up to bulk. 

Acid-alum bath—The following is typical of the formulas 
recommended by plate and film makers: 


Hypo 250 g 16 oz. 

Water 1000 ccm 64 oz. 
Dissolve and add: 

Sodium sulphite, dry 3l¢g YZ oz. 

Acetic acid, No. 8 186 g 3 oz. 

Alum 31 ¢g YZ oz. 

Water 312 com 5 oz. 


Dissolve the chemicals in this order. Some paper makers 
recommend the same bath, but with double the quantity of 
sulphite and alum, for developed prints. 


Acid-chrome alum bath— 


Sodium sulphite, dry 45 ¢ 34, OZ. 

Water 100 ccm LY oz. 
Stir well and add: 

Glacial acetic acid 20 ccm 154 min. 
Then add to the following, after the hypo is dissolved: 

Hypo 400 g 64 oz. 


Hot water 600 ccm 9 oz. 


FIXING AND CLEARING 125 


Finally, add: 


Chrome alum 20g 154 gr. 
Hot water 50 ccm 34, OZ. 


Make the total bulk up to 1000 ccm or 16 oz. 


Rapid ammonia fixing bath.—It is frequently recommended 
to add ammonium chloride to the fixing bath on the supposi- 
tion that ammonium hyposulphite is formed, that this fixes 
quicker, and is washed out more easily. If a 20 per cent solu- 
tion of hypo is used, the addition of from 2% to 5 per cent 
of ammonium chloride increases the rapidity of fixing. With 
a 40 per cent solution, it has no effect. The addition of 
10 per cent of ammonia water to a 20 per cent solution of 
hypo acts as quickly as the ammonium chloride. 

Resipues.—-To precipitate metallic silver from old hypo 
baths, from 6 to 8 g per liter (420 to 560 grains per gallon) 
of sodium hydrosulphite, Na,S,O,, should be added, with 
about half the quantity of caustic soda, and the bath heated 
to boiling to decompose excess of hydrosulphite. This treat- 
ment regenerates the hypo, and the bath can be used again. 

Addition of a saturated solution of sulphurated potash, the 
so-called liver of sulphur, may be used for precipitating the 
silver from old hypo baths. This should be done out of 
doors, as sulphuretted hydrogen is evolved. The mixture 
should be well stirred and the silver sulphide allowed to 
settle down; then some of the clear supernatant liquid should 
be collected in a graduate, and tested with a drop or two of 
liver of sulphur solution. A deep brown colour or blackish 
precipitate shows the presence of silver in solution, and then 
more sulphur compound should be added. 

A much more cleanly precipitant is zinc. This can be used 
either in scrap or mossy form. The liquid should be well 
stirred and allowed to settle; this operation should be re- 
peated three times at intervals of 24 hours. The clear liquid 


126 PHOTOGRAPHIC FACTS AND FORMULAS 


may be tested as suggested above. About three days is suff- 
cient, as a rule, to throw down the whole of the silver. 

One of the best methods of regaining the silver is to 
procure a sheet of brass, not too thin, and place in the barrel 
or jar at an angle, so that both sides are presented to the 
liquid. After about 48 hours, the whole of the silver will be 
precipitated in the metallic form on the brass and can usually 
be removed by bending a corner sharply two or three times, 
when the silver will spring off. The brass can then be put 
back into the vessel and allowed to remain another 24 or 48 
hours, when practically the last trace of silver will be ex- 
tracted. This thin coat is difficult to remove and may be left 
on until the next batch of residues is to be treated. 

Paper and print clippings and waste prints should be burnt, 
and the ashes collected and mixed with the silver sulphide 
from the old fixing baths. 

Platinum Residues—The developer and acid fixing baths 
from the platinotype process should be collected and prefer- 
ably boiled down to about one-fourth the volume. Then some 
saturated solution of ferrous sulphate should be added, the 
mixture boiled for an hour, and the platinum filtered out. 

Gold baths ——Old gold toning baths may be treated in the 
same way as the platinum solutions, after acidulating with 
hydrochloric acid. 

It does not pay a photographer to refine his own residues. 
All the silver residues should be mixed together, and the gold 
and platinum kept separate, and sent to a refiner, who will 
allow market value of the metals minus a small charge for 
refining. 

Hypo ELiminatTors.—It is an open question whether the 
use of chemicals to destroy the last traces of hyposulphite of 
soda and the hyposulphites of silver is justifiable if perma- 
nency of results be the aim. Their action is probably in most 


FIXING AND CLEARING Ley, 


cases to convert these salts into tetrathionates ; and, as a nega- 
tive or print can be practically freed from hypo in half an 
hour by proper washing, their use is only allowable in cases of 
great pressure of time or shortage of fresh water. The fol- 
lowing have been recommended. 

Zinc hypochlorite (Hart) — 

Chloride of lime 10g 77 gr. 
Water 500 ccm 8 oz. 
Rub the lime into a cream with a little water; then add the 

rest of the water, and add to: 

Zinc sulphate 20 g 154 gr. 
Water 500 ccm 8 oz. 
Shake well and filter or allow to stand until the precipitate 
subsides, and decant the supernatant liquid. For use dilute 
with 9 parts of water; immerse the negatives or prints for 
about 3 minutes, and then briefly wash and dry. Sodium or 
potassium hypochlorites may be made and used in the same 
way, employing the alkaline carbonates instead of the zinc 

salt. 

Potassium permanganate, in 1 per cent solution, may also be 
used, enough being added to water to give a pink tinge, and 
the negatives bathed in the solution until the colour is no 
longer discharged, repeated baths being used. Potassium 
percarbonate in 1 per cent solution has also been sold com- 
mercially as Hypax or Hypono. Sodium perborate can be 
used in the same way. Potassium or ammonium persulphate 
in 1 per cent solution, made alkaline with ammonia, may also 
be used. The former has been sold as Thioxydant, Anthion, 
etc. A 5 per cent solution of hydrogen peroxide may also be 
used. 

HARDENING BatHs.—Sometimes used for negatives and 
prints in hot weather. Thorough washing so as to eliminate 
all hypo must precede these baths: 


128 PHOTOGRAPHIC FACTS AND FORMULAS 


A. Alum 10 per cent solution, or 

B. Chrome alum 2 per cent solution, or 

C. Formaldehyde 10 per cent solution 
With the last bath, freedom from hypo is not so essential. 
Practically, the use of these baths has been rendered obsolete 
by the use of the chrome alum fixing baths. 

CLEARING Batus.—These baths are not much used at the 
present day when the use of sulphite and the newer developers 
prevents the staining of the gelatine, which was so prone to 
occur in the early days of the gelatine plate, when plain 
pyrogallol developer was used. The well-washed negatives 
may be immersed in: 

Potassium permanganate lg /.f oY. 
Water 1000 ccm 16 oz. 
for 5 minutes, then rinsed in water and immersed in a 1 per 
cent solution of potassium metabisulphite, or sodium bisul- 
phite, or in: 


Alum 200 g 3 02. 
Citric acid 652g 1 oz. 
Water 1000 ccm 16 oz. 
Or: 
Alum 50 g 34 OZ. 
Citric acid 50 g YW Oz. 
Ferrous sulphate 150 ¢ 2% oz. 
Water 1000 ccm 16 oz. 
Or: 
Chrome alum 25g 192 ger. 
Sodium bisulphite 100 g 770 gr. 
Water 1000 ccm 16 oz. 
Or: 
Thiocarbamide 20 g 154 gr. 
Citric acid 10g 77 gr. 
Water 1000 ccm 16 oz. 


FIXING AND CLEARING ed 


Dichroic, red or green fog, is practically unknown at the 
present day, but it was very prevalent in the early days of 
dry plate work, and showed itself mainly in the shadows as a 
more or less deep red colour by transmitted light, which was 
green by reflected light. The remedy for this (Abney) is 
to bleach the negative in: 


Ferric chloride 24¢ 184 gr. 
Potassium bromide TS oe Lon eT 
Water 1000 ccm 16 oz. 


Wash well and then redevelop. 
ALUMS AS HARDENING AGENTS.— 


Potash alum 6 parts 
Ammonia alum 5.6 parts 
Aluminum sulphate 4.2 parts 
Aluminum chloride, anhydrous 1.6 parts 
Aluminum nitrate 4.5 parts 
Chrome alum 2 parts 


The above quantities will render 100 parts of dry gelatine 
insoluble in hot water. Basic chrome alum is the most 
effective agent. This is made as follows: 


Chrome alum 100 g 768 gr. 

Hot water 800 ccm UD 
When dissolved, add: 

Ammonia quant. suff. 


to form a slight permanent precipitate after stirring well; 
then filter, and make bulk to 1000 ccm, or 16 oz. 


Intensification 


Tue Mercury INTENSIFIER.—This is probably the most 
generally used of all intensifiers. The silver image is treated 
with mercuric chloride or bromide until bleached, then 
washed, and blackened by various reagents. The mercuric 
halide solution is sensitive to light and should be kept in the 
dark. It is extremely poisonous when taken internally, but 
the absorption by the skin, even in the case of cuts and abra- 
sions, is practically harmless. Make up the following mer- 
cury solution: 


Mercuric chloride 20 g 154 gr. 
Salt 20 g 154 gr. 
or Ammonium chloride 20 g 154 gr. 
or Hydrochloric acid 3 ccm 23 min. 
or Potassium bromide 20 g 154 gr. 
Water 1000 ccm 16 oz. 


The purpose of these additions is to increase the solubility 
of the mercury salt, and the bromide gives greater increase 
of density than the others. The plate to be intensified should 
be perfectly free from hypo, and if dry, soaked in water for 
10 minutes, and then immersed in the mercury solution until 
the image seen from the back is white; on no account should 
the action be stopped before this point is reached. It should 
then be well washed in water acidulated with hydrochloric 
acid, 1: 300; about 5 minutes soaking in six successive baths 
may be used; then, after washing in running water for 10 
minutes, it may be blackened. The acid bath removes the 
mercury salt, which is tenaciously held by the gelatine, and 
might otherwise give rise to stains. This acid treatment may 
be avoided by the use of the following bleach: 


130 


INTENSIFICATION eal 


Mercuric chloride 20 g 154 er. 
Ammonium chloride TSC Cues OZ woe 
Hydrochloric acid 10g 77 gr. 
Water 1000 ccm 16 oz. 


The large proportion of the ammonium chloride is said to 
facilitate the removal of the mercury salt. 

The blackening may be effected with one of the following 
reagents : 

A. Ferrous oxalate developer, using 1 part of iron sulphate 
solution to 6 of oxalate; 

B. Amidol developer. Other developing agents with sul- 
phite may be used; 

C. Sodium sulphite, 5 per cent solution of the anhydrous 
or 10 per cent solution of the hydrated salt; 

D. Ammonia, 10 per cent solution of the strongest am- 
monia water. The bromide bleach does not give such satis- 
factory results with this as the chloride; 

E. Silver-potassio-cyanide (Monckhoven). This is pre- 
pared from: 


I. Silver nitrate 20 g 154 gr. 
Water 500 ccm 8 oz. 

II. Potassium cyanide 20 g 154 gr. 
Water 500 ccm 8 oz. 


Add three-fourths of I to II and shake thoroughly; a thick 
curdy white precipitate will be thrown down, which dissolves 
on shaking. If a perfectly clear solution is obtained, add 
more I until, after shaking and allowing to stand with occa- 
sional agitation for 10 minutes, there is a permanent white 
precipitate. The quantity of silver required depends on the 
strength of the cyanide, which varies considerably; in any 
case, a permanent deposit must be formed, even by adding 
more silver than above stated. This method of mixing is 
better than adding the cyanide to the silver. If the negatives 


132 PHOTOGRAPHIC FACTS AND FORMULAS 


are allowed to remain too long in this solution, they are 


reduced ; 
F. Mercuric-iodo-cyanide (Eder) : 


Potassium cyanide 5g 38 gr. 
Potassium iodide 2.598 are | Ogre 
Mercuric chloride 2.08 19 gr. 
Water 1000 ccm 16 oz. 


The bleached image first turns yellowish, then dark brown, 
and, if the plate be removed at this stage, it will generally be 
too dense for practical purposes; if the action is allowed to 
continue longer, the image turns a lighter brown and becomes 
more transparent ; 

G. Schlippe’s salt or sodium sulphantimoniate : 


Schlippe’s salt 25g 192 gr. 
Ammonia 10 ccm 77 min. 
Water 1000 ccm 16 oz. 


Make just before use and filter. Gives a brownish-red image 
which is too dense for ordinary work. This is useful for 
restoring negatives intensified with mercury, which have 
faded with course of time; 

H. Sodium sulphide 10¢g 77 gr. 

Water 1000 ccm 16 oz. 

Usually gives too much intensification for ordinary work; 

I. Formalin with caustic soda has been recommended for 
blackening the bleached images, but presents no advantage; 

J. Stannous tartrate (Helain) : 


Stannous chloride 20 g 154 gr. 
Tartaric acid 20 g 154 er. 
Water 1000 ccm 16 oz. 


This has also no special features to recommend it. 
Practically, it may be said that, assuming the original den- 

sity of the negative to be 1, the intensification given by A, B, 

C, E will be 2, by D about 2.5. Repeated bleaching with 


INTENSIFICATION 133 


mercury and development with ferrous oxalate will give any 
desired degree of increase. 

Mercuric Iodide (Edwards, Lumiére, etc.)—As originally 
recommended by Edwards, this was a solution of mercuric 
iodide in excess of iodide and hypo, as follows: 


Mercuric chloride 12'¢ 92 gr. 

Water 650 ccm 10 oz. 
Dissolve and add: 

Potassium iodide Sie 253 er. 

Water 100 ccm jusheye. 
And, finally: 

Hypo 27 g 207 gr. 

Water 250 ccm 4 oz. 
MM. Lumiére suggested: 

Mercuric iodide 10g 77 gr. 

Sodium sulphite, dry 100 g 770 gr. 

Water 1000 ccm 16 oz. 


This is an improvement on the first formula. The negatives 
assume a dark brown colour, but the image is not stable and 
soon turns yellow. It is advisable, therefore, to treat the 
darkened image with a developer, which renders it per- 
manent. Welborne Piper proposed the following: 


A. Mercuric chloride 50 g 384 gr. 
Hot water 1000 ccm mnLG iz, 
B. Potassium iodide 50 ¢ 384 gr. 
Cold water 250 ccm 4 oz. 


Add B to A gradually, shaking after each addition until the 
solution becomes clear, and, if necessary, heating. After all 
B has been added and the solution is clear, allow to cool and 
filter out any red precipitate formed. The negatives should 
be bleached in this solution, washed and treated with sodium 
sulphite or ammonia, or redeveloped, and well washed. 
Mercuric Sulphocyanide (Agfa).—This was patented in 


134 PHOTOGRAPHIC FACTS AND FORMULAS 


Germany by the Aktiengesellschaft f. Anilinfabrikation. A 
similarly acting solution can be made as follows: 


Mercuric chloride 187 g 3 Oz. 

Hot water 750 ccm 12 oz. 
Add: 

Ammonium sulphocyanide 229 2. J Oly Onn 

Water 250 ccm 4 oz. 


For use dilute 1 part with 10 parts of water. The negative 
turns black at once; but, if left too long, the intensification is 
reduced. The images are not stable unless a developer is 
applied. 

THE CHROMIUM INTENSIFIER (Eder, Welborne Piper and 
Carnegie) —This method of intensification has deservedly 
received considerable attention, being less liable to stain and 
much less poisonous than many others. The negatives need 
not be absolutely free from hypo, as the bleaching bath 
oxidises this, though, if much hypo be present, it may be 
necessary to apply the bleaching bath twice. Two stock 
solutions are required: 


I. Potassium bichromate 50 g 384 gr. 
Water 1000 ccm 16 oz. 
II. Hydrochloric acid, pure 100 ccm 1 oz. 
Water 1000 ccm 10 oz. 

The bleaching baths are: 

Wek B ec 

Stock solution I oe 64 64 parts 
Stock solution II 3 16 64 parts 
Water 128 80 32 parts 


Immerse the negative in the solution until the image on the 
glass side appears bleached, then wash until the yellow stain 
is removed, and develop with amidol in white light. Other 
developers may be used, without bromide, but the image 
requires exposure to diffused daylight, and they are less 


INTENSIFICATION 135 


satisfactory. A gives the strongest and C the least intensifi- 
cation. The process may be repeated as often as required. 
As a variant the following may be used: 


Chromic acid Zoe 19:2 or. 
Salt 2.0 2 19.2 gr. 
Water 1000 ccm 16 oz. 


The procedure described above should be followed. The acid 
and salt may be kept in stock solutions, say 10 per cent, and 
mixed as required. 

A convenient form of a dry salt, the chlorochromate, may 
be prepared as follows (Lumiére & Seyewetz) : 


Ammonium bichromate 82g 1265 gr. 
Hydrochloric acid, 
sp. gr. 1.16 364 ccm 12 0z., 160 min. 


Place the acid in an evaporating dish, add the ammonium 
salt, and evaporate until dry. The result will be 100g 
(1543 gr.) of ammonium chlorochromate, which may be kept 
in a dry state or in a 10 per cent solution by dissolving in 
1000 ccm (32 oz.) distilled water. Of this, 30 ccm (210 min.) 
should be diluted to 1000 ccm (16 oz.) to form a convenient 
bleacher. The equivalent weights of the potassium salt may 
be used, that is, 100 g or 1543 gr. 

THE COPPER-SILVER INTENSIFIER.—This intensifier is par- 
ticularly valuable for black and white or line negatives, and 
gives great intensification. The bleaching solution is pre- 


pared from: 
I. Cupric sulphate ll5¢g 2 oz. 
Hot water 500 ccm 8 oz. 
II. Potassium bromide ll5¢ 2 OZ. 
Hot water 500 ccm 8 oz. 


Mix and allow to cool. The negative should be bleached in 
this, washed no longer than 2 minutes, and blackened in: 
Silver nitrate 10 per cent solution 


136 PHOTOGRAPHIC FACTS AND FORMULAS 


If still greater density be required, the negative should be well 
washed after bleaching and redeveloped with any ordinary 
developer, the silver treatment being omitted. Or, after 
washing, the negative may be blackened with a 0.5 per cent 
solution of sodium sulphide. 

As an improvement on the silver nitrate, which may cause 
stains, Namias recommends silver oxalate. To prepare this, 
take: 


Silver nitrate 10g 77 gr. 

Water 100 ccm 2 oz. 
Dissolve, and add: 

Potassium oxalate, neutral 6g 46 gr. 

Water 50 ccm 1 oz. 


Allow the silver oxalate to settle down, decant the water, and 
add the precipitate to 1000 ccm (16 oz.) water. Shake the 
solution every time before applying to the bleached negative. 
The process is applicable to papers as well as plates, and it is 
advisable to subsequently immerse in a 10 per cent solution 
of hypo for a few minutes and wash well. 

THe Copper-Tin INTENSIFIER.—In this the final image 
consists of a mixture of tin and silver compounds, and the 
intensification is due to a great extent to the non-actinic colour 
of the deposit, which is a warm brown. Bleach the negative 
in: 


Cupric chloride 30 g 230 gr. 

Hydrochloric acid 3 ccm 23 min. 

Water 1000 ccm 16 oz. 
Wash thoroughly and immerse in the following: 

Stannous chloride 40 g 307 gr. 

Water 400 ccm 4 oz. 
To which is added: 

Caustic soda 30 g 230 gr. 


Water 100 ccm 1 oz. 


INTENSIFICATION 137 


This should be added cautiously to the tin solution, with con- 
stant stirring, so that the precipitate first formed is not quite 
cleared up. The solution should then be filtered, and the bulk 
made up to 1000 ccm (16 oz.) with water. A variation of 
this method is to treat the bleached image with a 5 per cent 
solution of caustic soda, wash, and then with 10 per cent of 
stannous chloride. The cupric chloride may be replaced by: 


Cupric sulphate 44¢ 34 gr. 
Salt 20.8 g 160 gr. 
Hot water 1000 ccm 16 oz. 


Mix and allow to cool before use. 

CoprperR FERROCYANIDE INTENSIFIER.—This is very rarely 
used, and is apt to give too great intensification. The degree 
of increase depends on the duration of the action of the bath 
and the consequent warmth of-colour. Two stock solutions 
are required: 


1. Cupric sulphate 72g 54 gr. 
Potassium citrate, neutral 28 g 215 gr. 
Water 1000 ccm 16 oz. 

II. Potassium ferricyanide 6g 46 er. 
Potassium citrate, neutral 28g CRNA 
Water 1000 ccm 16 oz. 


Mix in equal quantities just before use. No. II solution must 
be kept in the dark. A variation of this is to mix the two 
solutions and to add enough strong ammonia to form a clear 
solution. 

THE URANIUM INTENSIFIER.—Except for extremely thin 
_and flat negatives, this is not to be recommended. The 
degree of intensification depends upon the ratio of the 
uranium to the ferricyanide: 

I. Uranium nitrate 100 g 768 gr. 

Glacial acetic acid 40 ccm 300 min. 
Water 1000 ccm 16 oz. 


138 PHOTOGRAPHIC FACTS AND FORMULAS 


II. Potassium ferricyanide 40 ¢ 307 gr. 
Potassium oxalate 10g 77 gr. 
Glacial acetic acid 40 ccm 300 min. 
Water 1000 ccm 16 oz. 


If mixed in equal volumes, a reddish brown image is ob- 
tained; 1 part I and 2 parts II give a reddish image; 5 parts I 
and 1 part II give a brown. The colour is also dependent to 
some extent on the duration of the action of each bath. The 
negatives should be washed in a 2 per cent solution of citric 
acid, or 1 per cent oxalic or glacial acetic acid. If plain water 
be used, about five changes at intervals of 5 minutes are 
enough. Prolonged washing in running water will com- 
pletely remove the intensification, generally first in patches. 
Tue Leap INTENSIFIER.—This gives very great intensifi- 
cation and is only suitable for black and white line work: 


Lead nitrate 46 g 353 gr. 
Potassium ferricyanide 70g 537 gr. 
Glacial acetic acid 20 ccm 154 min. 
Water 1000 ccm 16 oz. 


This will keep in the dark. The lead salts are rather tena- 
ciously retained by the gelatine; it is advisable to immerse the 
negatives in a 5 per cent solution of nitric acid for 5 minutes, 
and then wash. If the negative be subsequently developed, 
rather less intensification is given. By applying a 10 per 
cent solution of chromic acid to the bleached negative, an 
orange image is obtained, which is very non-actinic, and the 
lines remain clear. Treatment with a 2 per cent sodium 
sulphide solution gives the greatest increase. 

QUINONE INTENSIFIER (Lumiére)—This has not come 
into general use, and the intensification is practically depen- 
dent on a change of colour of the image into a more non- 
actinic one; but some compound of silver and bromine is 
present. 


INTENSIFICATION 139 


A. Quinone aie: 38 gr. 
Potassium bromide 25g 192 gr. 
Water 1000 ccm 16 oz. 

Or: 

B. Sodiumquinone sulphonate 10 ¢ Ips 
Potassium bromide 25g 192 gr. 
Water 1000 ccm 16 oz. 


The negative after treatment may look muddy. It should be 
briefly rinsed with water, and immersed in a 10 per cent 
solution of ammonia. The colour given by A is reddish 
brown, by B yellowish brown. Ammonia, with short action, 
gives great intensification, both images becoming dark brown; 
after 10 minutes’ action, the original colours are again formed 
with less intensification. The carbonates of sodium and 
potassium also turn the images brown, giving also great in- 
tensification. Hypo reduces the image without altering the 
colour of plates treated with A, but with B the final colour 
is a reddish-yellow. Sulphites or bisulphites convert the 
image of A into a greenish-brown; in the case of B, into a 
dark brown. An amidol developer acts like sulphite on A, 
but gives yellowish-black images with B. 

Bromo-lopipE oF Copper (Jenney).— 


Cupric sulphate BF e 288 gr. 

Water 500 ccm 8 oz. 
When dissolved, add: 

Potassium iodide Og 69 gr. 

Potassium bromide 23g 177 gr. 

Water 500 ccm 8 oz. 


A slight precipitate of copper iodide is formed, which should 
be filtered out. The negative should be immersed in the solu- 
tion until bleached to a bright yellow colour, which takes 
from 5 to 15 minutes, and then well washed and immersed 
in a saturated solution of sodium sulphite to which a few 


140 PHOTOGRAPHIC FACTS AND FORMULAS 


grains of silver nitrate have been added. This gives a brown- 
ish-black image. By applying a hydrochinon developer, a 
reddish image is obtained, and rodinal gives a brown. After 
intensification, the negative or print should be well washed 
in water. Both bleaching and redevelopment should be car- 
ried out in bright daylight. This is very rarely used and 


presents no particular advantages. 


Dyer INTENSIFICATION.—Partially bleach the images in: 


Potassium ferricyanide 0.34 g 
Ammonium bichromate 0.068 g¢ 
Glacial acetic acid 8.5 ccm 
Water 1000 ccm 
Then wash, and immerse in: 
Victoria green 0.26 g 
Safranin 0.52 g 
Glacial acetic acid 8.5 ccm 
Water 1000 ccm 


Ppa 
0.5 gr. 
64 min. 
16 oz. 


1.25 gr. 
2.5 gr. 
64 min. 
16 oz. 


Dye for 30 to 120 seconds and wash for 5 minutes. 


Reducers 


Potassio-FERRIC OXALATE (Belitzski)—A very conveni- 
ent reducer, which may be kept as a stock solution in the dark, 
and repeatedly used until it turns yellow, which is a sign of 
exhaustion: 


Potassium ferric oxalate 50 g 384 gr. 

Water 1000 ccm 16 oz. 
Dissolve, and add: 

Sodium sulphite, dry 20 g 154 ger. 
This forms a blood red solution, to which should be added: 

Oxalic acid, cryst. I5¢ 115 gr. 


- Shake the solution until a bright green colour is formed, free 
from any tinge of yellow; then pour off from any undissolved 
crystals, and add: 

Hypo 250 g 4 oz. 
Shake until dissolved. 

It is preferable to soak the negative in water before apply- 
ing the reducer. Thorough washing should follow the reduc- 
tion. Instead of the potassium ferric oxalate, the following 
may be used: 

Ferric chloride 32.5 g 500 gr. 
Neutral potassium oxalate 62.5 ¢ 950 gr. 
This will make the above quantity of potassium ferric oxalate, 
and the potassium chloride formed is negligible. The reducer 
tends to attack the shadows more than the high-lights, there- 

fore, increases contrasts. 

HyYPocHLoRITE AND ALuM (Debenham).—An excellent 
reducer, which can be locally used by immersing the negative 
in the solution and rubbing any part with a pad of absorbent 
cotton : 


141 


142 PHOTOGRAPHIC FACTS AND FORMULAS 


Chloride of lime 6g 46 gr. 
Make into a paste with a little water, and add to: 

Sodium carbonate, dry 4.5¢ 34 gr. 

Water . 250 ccm 4 oz. 


Shake thoroughly, filter, and wash the filter with successive 
portions of water to make the total bulk of the filtrate 
1000 ccm (16 oz.), then add: 

Chrome alum 4¢g 30 gr. 
Immerse the negative and rock the dish for a few minutes; 
then gently pass a pad of absorbent cotton, well wetted, over 
the surface. 


BICHROMATE.— 
Potassium bichromate 20 g 154 gr. 
Sulphuric acid 40 ccm 308 min. 
Water 1000 ccm 16 oz. 


Dissolve the bichromate, and add the acid. This has nothing 

particular to recommend it, and requires rather long washing 

to remove the yellow stain from the negative. 
PERMANGANATE (Namias).— 


Potassium permanganate 0.5 g 4 gr. 
Sulphuric acid 10 ccm 77 min. 
Water 1000 ccm 16 oz. 


It is preferable to mix this just before use, or stock solutions 
can be prepared by dissolving the permanganate in half the 
water, and the acid in the other half; the stock permanganate 
solution must be kept in the dark. This reducer acts evenly 
and can be used for prints as well as negatives. Should any 
brown stains appear, they may be removed by immersing the 
plates or prints in: 


Sodium sulphite, dry 75g 576 gr. 
Oxalic acid 30 g 230 gr. 
Water 1000 ccm 16 oz. 


Wash well after this bath. 


REDUCERS 143 


Iopip—E AND Hypo (Lainer)—An extremely slow acting 
reducer, which is useful in the case of negatives generally 
fogged: 


Potassium iodide 10g 77 gr. 
Hypo 250 g 4 oz. 
Water 1000 ccm 16 oz. 


The negative should be immersed in this solution for from 

8 to 10 hours, or until the desired reduction is attained, then 

well washed. Prints may also be reduced in the same way. 
Creric SULPHATE (Lumiere) .— 


Sulphuric acid 4 ccm 30 min. 
Water 200 ccm 3 02. 
Add: 
 Ceric sulphate 10g 77 gt. 
Stir until dissolved, then add: 
Water to 1000 ccm 16 oz. 


For use mix 1 part with 9 parts of water. This reduces the 
contrasts, and the negatives should be well soaked in water 
prior to immersion in the solution. For overexposed dense 
negatives, mix the above stock solution with an equal volume 
of water, and immerse the negative dry; care must be exer- 
cised, as the action is very rapid. There is no liability to stain, 
and the solution may be used still more dilute for prints. 
IoDo-CYANIDE.—Extremely poisonous, but clean acting: 


Iodine 6g 46 gr. 
Potassium iodide 18 g 138 gr. 
Water 30 ccm Y, oz. 


Rub the iodine and the iodide together in a mortar or graduate 
with a glass rod, add the water, and stir until complete solu- 
tion is obtained; then add: 
Water 970 ccm 15¥Y4 oz. 
Potassium cyanide lg 7.7 gt. 


144 PHOTOGRAPHIC FACTS AND FORMULAS 


This forms an excellent non-staining reducer for developed 
prints if diluted with 10 times its volume of water. 

Mercury AND CYANIDE (Eder).—An extremely poisonous 
but non-staining reducer: 


Mercuric chloride Doe 19 gr. 

Water 1000 ccm 16 oz. 
Dissolve, and add: 

Potassium iodide 2:58 19 gr. 


Red mercuric iodide is precipitated, which is dissolved by 
the addition of: : 
Potassium iodide 5g 38 gr. 
This acts rapidly. It is suitable for developed prints if 
diluted with 10 parts of water. A variant of this is to replace 
the iodide with a like quantity of sodium carbonate crystals. 
Cupric CHLORIDE (Spiller). — 


A. Alum 100 g 134 oz. 
Cupric chloride 100 g 134 oz. 
Salt 200 g 3Y4 oz. 
Hot water 1000 ccm 16 oz. 


Dissolve, and filter when cold. 
B. Saturated solution of salt. 
For use mix in equal volumes. When the negative is nearly 
sufficiently reduced, wash. This cannot be recommended, as 
the reducing action continues too much during the washing. 
A variation of the above (Fourtier) has been suggested: 
Cupric sulphate 5g 38 gr. 
Water 100 ccm 2 oz. 
Dissolve, and add solution of potassium carbonate until no 
further precipitate is formed. Collect the precipitate on a 
filter, wash with several changes of water, and then dissolve 
in: 
Hydrochloric acid q. Ss. 
Water 25 ccm Y, 02. 


REDUCERS 145 


Enough acid should be used to dissolve the precipitate. To 
the clear solution add: 

Ammonia q. Ss. 
This forms a deep blue, clear solution to which should finally 
be added: 

Hypo 5g 38 gr. 
Water to 1000 ccm 16 oz. 
This is said to be particularly useful for local reduction of 
prints. The print should be well soaked in water, placed 
face up on a sheet of glass, and the reducer applied with a 
pad of absorbent cotton. The action is at once stopped by 
well washing with water. This has been but little used in 
practice, and the method of making is a roundabout way of 

making cupric chloride. An easier way would be to mix: 


Cupric sulphate 5¢g 38 gr. 
Salt 200.2 18 gr. 
Water 100 ccm 2 oz. 


then add enough ammonia to form a clear solution. 

Ferric chloride and sulphate either alone or with citric acid 
have been recommended as reducers; but they are extremely 
liable to stain the gelatine by the deposition of basic iron salts 
and should not be used. 

Hypo AND FERRICYANIDE (Farmer ).—This is prepared as 
wanted by adding a little 10 per cent solution of potassium 
ferricyanide to a 20 per cent plain solution of hypo. The 
quantity of ferricyanide to be added depends on the result 
desired; the weaker the solution, the more even the action, 
that is to say, the less the shadows are attacked. A pale 
yellow coloured mixture is best. The colour of the solution 
rapidly disappears in use, and this is a sign of exhaustion. A 
fresh mixture should be applied rather than allow an old one 
to act. The action of this bath is the conversion of some of 


146 PHOTOGRAPHIC FACTS AND FORMULAS 


the silver into silver ferrocyanide, which dissolves in the 


hypo. 
Homolka suggested as a stable reducer: 
Potassium ferricyanide 50 g 384 gr. 
Sodium amido-acetate 200 ¢ 30z., 224 gr. 
Water 1000 ccm 16 oz. 


For use dilute with from 5 to 10 parts of water, and, when 
the desired reduction is attained, immerse the negative in an 
acid fixing bath. 

Another modification of Farmer’s reducer is the following 
(Haddon), which has the advantage of keeping well: 


Potassium ferricyanide 10¢g 77 gr. 
Ammonium sulphocyanide 20 g 154 gr. 
Water 1000 ccm 16 oz. 


The negative should be soaked in water before immersion. 

AMMONIUM PERSULPHATE.—The particular value of this 
reducer is that it attacks the densest parts of a negative more 
than the shadows, thus considerably reducing contrasts; but 
its action is much complicated by intentional or accidental 
additions, such as acid, chlorides, and iron salts, which may 
occur by keeping the solution or the use of ordinary tap 
water. A 5 per cent solution in distilled water should be 
made, and allowed to stand for 3 to 4 hours, or 15 ccm 
(105 min.) of 10 per cent solution of sulphuric acid, or 
1 ccm (8 min.) of 5 per cent solution of ammonia iron alum 
added per liter (16 0z.). The following solution has been 
advised (Bennett), and can be kept for a considerable time 
in stock : 


Ammonium persulphate 125 ¢ 2 oz. 
Sodium sulphite, dry 10g 77 gr. 
Sulphuric acid 10g 77 min. 
Water 1000 ccm 16 oz. 


For use dilute with from 4 to 8 parts of water, according to 


REDUCERS 147 


the rapidity of action desired. Immersion in a 5 per cent 
solution of sodium sulphite has been recommended as a stop 
bath, but this is liable to cause red stains. The best plan is to 
wash rapidly. 

The following mixture (Puddy) acts on the shadows be- 
fore the high-lights: 


Ammonium persulphate 50 g 384 gr. 
Ammonium sulphocyanide 25 g 192 gr. 
Water 1000 ccm 16 oz. 
The following solution acts on all densities nearly alike: 
A. Potassium permanganate 0.25 g 1.92 gr. 
Sulphuric acid, 10% ‘solution 15 ccm 115 min. 
Water 1000 ccm 16 oz. 
B. Ammonium persulphate 25 g 192 gr. 
Water 1000 ccm 16 oz. 


For use mix 1 part A with 3 parts B. The separate solutions 
keep well, but should not be mixed until required. The time 
of reduction varies from 1 to 3 minutes, and greater control 
is obtained by diluting the mixture with an equal volume of 
water. As soon as the desired reduction is reached, immerse 
the negative in a 1 per cent solution of potassium metabisul- 
phite for 5 minutes, and wash. 

QUINONE ReEpbucer (Lumiere ).—This acts like ammonium 
persulphate, that is, reduces the high-lights more than the 
shadows: 


Quinone 5g 38 gr. 
Sulphuric acid 20 ccm 154 min. 
Water 1000 ccm 16 oz. 


As soon as the desired reduction is reached, the plate should 
be immersed in a 2 per cent solution of sodium bisulphite, 
washed, and dried. 

HaRMONISING HarsH NeEcaTives.—This method of re- 
ducing the over-dense parts of negatives has been replaced by 


148 PHOTOGRAPHIC FACTS AND FORMULAS 


the use of the persulphate, but it is still valuable. The nega- 
tive should be immersed in: 


Hydrochloric acid 25 ccm 192 min. 
Potassium bichromate 8g 61 gr. 
Alum 40 g 307 gr. 
Water 1000 ccm 16 oz. 


Leave until bleached through to the glass, then thoroughly 
wash until all traces of yellow disappear. It should then be 
developed with a slow acting developer, such as hydrochinon, 
about one-fourth the usual strength, and development con- 
tinued until, on examination of the negative from the glass 
side, it is seen that the shadows and half tones are fully 
developed, while the high lights still show white silver chlo- 
ride. The negatives should then be fixed and washed. This 
method is also useful for halated negatives. The following 
modified bleacher may be used: 


Chromic acid 5g 38 gr. 
Potassium bromide 10g 77 gr. 
Water 1000 ccm 16 oz. 


The method of using is as above, or, to hasten the removal of 
the yellow stain, apply a 2.5 per cent solution of potassium 
metabisulphite or sodium bisulphite. 

MECHANICAL Repuction.—This is a method but little 
practiced and rather dangerous, except in expert hands. It 
consists in local attrition of the gelatine, preferably with a 
chamois leather moistened with denatured alcohol (methylated 
spirit). Another abrasive has also been suggested (Baskett), 
and consists of a mixture of equal parts of terebene, olive oil, 
and metal polish. This is also used with chamois leather, and 
acts more quickly than the alcohol. After its use, the negative 
should be rubbed two or three times with benzol to remove 
the grease. Some commercial metal polishes may be used 
without any admixture, but, after shaking well, should be 


REDUCERS 149 


allowed to stand for a minute or two for the coarser particles 
to subside. 


Varnishes 


VARNISHES.—The increasing use of bromide and develop- 
ment papers instead of printing-out papers, and, in a minor 
degree, the general adoption of films by amateur workers, has 
rendered less obligatory the use of negative varnishes for the 
protection of the gelatine surface. In the case of celluloid 
films, it is obvious that the solvents used in the varnishes must 
not attack the celluloid; therefore, the aqueous varnishes are 
preferred, though they do not give so much protection as the 
others. Varnishes may be classified as “hot” and “cold” 
varnishes, the former being applied to a heated negative, 
while the latter may be applied to the cold negative. In the 
first case, the negatives should be warmed in front of a fire 
or over a gas or spirit burner until the glass is as hot as the 
back of the hand can comfortably bear. 

Hot VARNISHES.— 


Orange shellac 752 576 gr. 
Gum sandarac 75g 576 gr. 
Alcohol, 96% 1000 ccm 16 oz. 
Castor oil 2 ccm 15 min. 


Allow the mixture to stand with frequent shaking until the 
resins have dissolved; then filter. There is frequently some 
trouble in clarifying varnishes, as the fine insoluble particles 
will not easily filter out. The remedy is to add about 2 per 
cent by weight of some inert powder, such as finely powdered 
pumice stone or tripoli, shake well, and filter. Another 
formula: | 


Orange shellac 50 g 384 gr. 
Gum elemi I5¢g 115 gr. 
Alcohol 1000 ccm 16 oz. 


150 


VARNISHES 
or: 
Gum mastic 8¢g 
Ether 250 ccm 
Gasoline 750 ccm 


151 


61 gr. 
SoZ 
11 oz. 


Not advisable, as the vapours are very explosive when mixed 


with air. Another: 


Gum sandarac 100 g 
Camphor 10¢g 
Venice turpentine 10g 
Oil of lavender 20 ccm 
Alcohol 1000 ccm 
Or: 
Orange shellac 200 g 
Gum sandarac 50 g 
Gum mastic 5g 
Gum dammar 5g 
Castor oil 5 ccm 
Alcohol 1000 ccm 
CoLp VARNISHES.—Aqueous shellac 
house) : 
Orange shellac 80 g 
Borax | 20 g 
Sodium carbonate, cryst. 20 g 
Glycerine 5 ccm 
Water 1000 ccm 


768 gr. 
77 gr. 
7PM Tee ¢ 

154 min. 
16 oz. 


1536 gr. 

384 gr. 

38 gr. 

38 gr. 

38 min. 

16 oz. 
varnish (Water- 


614 ger. 
154 gr. 
154 gr. 
38 gr. 
16 oz. 


Dissolve the borax and soda in half the water, add the 
shellac, and boil until dissolved; then add the glycerine and 
enough water to make the total bulk, and filter when cold. 


Gr: 
Bleached shellac 100 g 
Borax 258 
Sodium carbonate, cryst. 6g 


1 3/5 oz. 
192 gr. 
46 gr. 


152 PHOTOGRAPHIC FACTS AND FORMULAS 


Glycerine 3.ccm 23 min. 

Water 1000 ccm 16 oz. 
The method of making is as above. Or: 

Bleached shellac 150 g PAPA Ta 

Alcohol 300 ccm 5 1/3 oz. 
Dissolve, and add: 

Ammonia 225 ccm 4 oz. 

Glycerine 7 ccm 54 min. 

Warm water 1000 ccm 16 oz. 


The above are particularly suitable for films. When using 
bleached shellac, it is essential to procure freshly bleached lac, 
or that which has been kept under water, as, when exposed to 
the air, this loses its solubility to a great extent. Dichlor- 
hydrin is an excellent solvent for bleached shellac, when 
warmed, but this varnish cannot be used for films, as it dis- 
solves the celluloid. 

An excellent varnish (Valenta) is made as follows: 


Gum dammar Fe 576 gr. 
or Gum mastic 60 g 460 gr. 
Carbon tetrachloride 1000 ccm 16 oz. 


If the mastic is used, it is necessary to heat to obtain perfect 
solution. Both varnishes give hard surfaces, which take 
retouching well. 

Epichlorhydrin and dichlorhydrin have also been recom- 
mended (Valenta) as solvents for varnishes, but have found 
little use. The following are suitable formulas: 


Copal 20 g 154 gr. 
Epichlorhydrin 70 ccm 1 oz. 
Digest on a water bath until dissolved, and add: 
Alcohol 770 ccm Lio: 
Epichlorhydrin 160 ccm 4 oz. 


Then filter. This gives a very hard film that dries quickly, 


VARNISHES 153 


may be used either as a hot or cold varnish, and takes the 
retouching pencil well. 

Matt VARNISHES.—These are generally used on the backs 
of negatives either to hold back certain parts in printing, or 
to facilitate working up with pencil or crayon: 


Gum sandarac, powdered 53 g 400 gr. 
Gum dammar l6g 120 gr. 
Ether — 700 ccm 11% oz. 


Allow to stand with frequent shaking until dissolved, then 
filter, and add: 


Benzol 300 ccm 434 oz. 
and: 
Alcohol lto5ccm 7to35 min. 


The quantity of alcohol determines to some extent the fine- 
ness of the matt grain. The following may also be used: 


Gum sandarac, powdered 722 504 gr. 

Ether 715 ccm 11¥4 oz. 
Shake until dissolved, filter, and add: 

Toluol 285 ccm 4¥4 oz. 


This does not give such fine grain as the former. 

For celluloid negatives the above varnishes with alcohol- 
ether solvents are not suitable, as the latter attacks the base. 
The following is suitable: 

Amber 25:2 192 gr. 
Benzol 1000 ccm 16 oz. 
The amber should be added in fine pieces, and the mixture 
digested in a warm place for two or three days, with occa- 
sional shaking, until the resin dissolves, then filter. 

There is frequently trouble when making varnishes, from 
the gums and resins compacting into a solid mass at the bot- 
tom of the bottle. This may be avoided to a great extent by 
using a wide-mouth bottle and suspending the resins in a 
little bag of fine muslin at the top of the liquid. As the resins 


154 PHOTOGRAPHIC FACTS AND FORMULAS 


dissolve, the solution sinks to the bottom of the bottle, and 
fresh solvent takes its place. This also frequently obviates 
the necessity of filtering. Another plan is to mix the resins 
with coarse glass grains or beads, about half the size of a 
grain of wheat. 

DEVARNISHING NEGATIVES.—Sometimes it becomes neces- 
sary to remove the varnish from negatives and this usually 
can be accomplished by soaking in strong alcohol, and then 
using gentle friction with a pad of absorbent cotton. It is 
preferable to use only just enough alcohol to cover the surface 
of the negative, and to apply two or three successive alcohol 
baths. A more energetic solvent is a 2 per cent solution of 
caustic potash, or soda, or ammonia in alcohol, which may be 
used for the first bath, and then followed by clean alcohol. 

PRINT VARNISH.—Sometimes used for brightening up 
matt surface papers: 


Gum sandarac 110¢ 134 oz. 
Benzol 400 ccm 64 oz. 
Acetone 400 ccm 6%4 oz. 
Alcohol, 90% 200 ccm JO2; 
Or: 
Gum dammar 60 g 1 oz. 
Ether 500 ccm 8 oz. 
Benzol 500 ccm 8 oz. 


These may either be applied with a brush locally to the 
shadows or the prints floated face downwards on the varnish. 
BLACK VARNISH.— 


- Shellac 200 g 3 1/5%07 
Denatured alcohol 1000 ccm 16 oz. 
Aniline black, spirit soluble l5¢ 115 gr. 

ALCOHOLIC CoLp VARNISHES (Valenta) — 
Gum sandarac 180 g 1382 gr. 


Alcohol, 96% 1000 ccm 16 oz. 


VARNISHES £50 


Oil of lavender 10 ccm 77 min. 
Or: 
Gum sandarac 100 g 768 gr. 
Benzol 400 ccm 64 oz. 
Acetone 400 ccm 6% oz. 
Alcohol, 96% 200 ccm 3% oz. 
CELLULOID OR ZAPON VARNISH.— 
Pyroxyline or celluloid scraps 20g 154 gr. 
Amy] acetate 1000 ccm 16 oz. 


Allow to stand for some time with frequent shaking until 
solution take place, and then allow to stand three or four days 
to settle. This takes a very long time to dry. Or: 


Pyroxyline or celluloid scraps 12¢ 21st: 
Amy] acetate 400 ccm 6 oz. 
Benzol — 400 ccm 6 oz. 
Acetone 200 ccm 3 02. 


This is also suitable for prints. A 5 per cent solution of 
pyroxyline in equal volumes of amyl acetate and alcohol can 
be used to protect metal work, can be applied either with a 
brush or spray, and is quite invisible ; sometimes butyl acetate 
is used instead of the amyl compound. Greater adhesion is 
obtained with the following: 


Pyroxyline 37.5 g 288 gr. 
Shellac 37.5 g 288 gr. 
Amyl acetate 500 ccm 8 oz. 
Benzol 250 ccm 4 oz. 
Methyl alcohol 250 ccm 4 oz. 


The film thus obtained is not so lasting as the plain pyroxyline 
varnish. Black varnish may be made by incorporating lamp 
black, when the varnish will be more or less matt, or by the 
use of spirit-soluble nigrosine, when glossy surfaces will be 
obtained. Any coloured varnish may be made by dissolving 
oil-soluble aniline dyes in the solvents. 


156 PHOTOGRAPHIC FACTS AND FORMULAS 


CRYSTAL VARNISHES.—Lhese are sometimes used for lan- 
tern slides and transparencies : 


Gum dammar 125 ¢ 2 oz. 

Benzol 1000 ccm 16 oz. 
Or: 

Fused amber 125 ¢ 2 oz. 

Chloroform 1000 ccm 16 oz. 
Or 

Fused amber 200 g 3 0z. 

Gum sandarac 300 g 414 oz. 

Gum elemi 50 g 384 gr. 

Alcohol 1000 ccm 16 oz. 

Camphor 6g 46 gr. 


RETOUCHING VARNISHES.—Since the gelatine film, as well 
as many of the varnishes, will not take kindly to the retouch- 
ing pencil, it is customary to apply locally a retouching 
varnish or medium which leaves a surface with a slight tooth. 
These should be applied in very small quantities, a drop or 
two, gently rubbed with a circular motion with the finger tip | 
over the part to be retouched, and then allowed to dry: 


Gum dammar 20 g 96 gr. 

Turpentine, refined 100 ccm 1 oz. 
fcr 

Powdered resin 12.5 60 gr. 

Turpentine, refined 100 ccm 1 oz. 
OE: 

Gum dammar 6.6 g 32 gr. 

Turpentine, refined 50 ccm Y, oz. 

Benzol 50 ccm Y, oz. 

Oil of lavender 50 drops 10 drops 
Or: 

Gum dammar 20 g 154 gr. 

Venice turpentine 10g 77 gr. 


VARNISHES 157 


Turpentine 1000 ccm 16 oz. 
Nitrobenzol 100 ccm 1 oz., 288 min. 
RETOUCHING MEDIUM.— 
Pure American turpentine 43ccm LY oz. 
Oil of spike 14.2 ccm YA oz. 
Pale resin 28.3 g 1 oz. 
Raw linseed oil 0.5 ccm 8 min. 
Terebene 1.2 ccm 20 min. 
Amyl acetate 7 ccm Y4 oz. 


If the solution is too thick, dilute with turpentine. Apply as 
little as possible with the finger tip. 

Biocxinc-ouT MrepIum.— 

Gum sandarac 500 g 8 oz. 
Denatured alcohol 1000 ccm 16 oz. 
Dissolve by allowing to stand in a warm place with constant 
stirring, carefully decant from the residue, and add lamp 

black to give a suitable consistency. 

FIXATIVE FOR CRAYON oR PasTEL WorkK.—This also forms 
a good varnish for prints: 

Mastic 8.3 g 64 er. 
Amy]l acetate 500 ccm 8 oz. 
Dissolve with constant stirring, allow to stand some hours to 

settle, and mix with: ; 
Celluloid Dag 18.5 gr. 
Amy] acetate 500 ccm 8 oz. 
This should be applied with a spray diffuser. 

STRIPPING Fitms.—The film can be easily stripped from 
negatives by one of the following processes. First, lay the 
negative face up on a smooth support, and cut right through 
the gelatine down to the glass with a sharp knife, about one- 
eighth of an inch from the edges. Then level the plate, and 
pour on it a little of the following solution: 

_ Glycerine 37.5 ccm 288 min. 


158 PHOTOGRAPHIC FACTS AND FORMULAS 


Water 37.5 ccm 288 min. 
Hydrofluoric acid 37-5:ccm 288 min. 
Denatured alcohol to 1000 ccm 16 oz. 


Spread the solution with a brush or spill of paper, and allow 
to soak for about 5 minutes. Then try and strip the narrow 
cut edges; if these can be easily removed, the work may be 
proceeded with; if not, the plate should be left a little longer. 
When the film is loose, as shown by the above test, pour off 
the liquid carefully, taking care not to let the film slip. Pour 
on some of the above solution without the acid, leave for 2 or 
3 minutes, and then drain this off. Gently place a piece of 
smooth waxed paper or thin celluloid over the negative, and 
lightly squeegee into contact; on lifting the paper, the film 
will be removed with it, and can be transferred to another 
support. Great care must be taken in the use of the above 
solution, as it attacks the fingers and all glass. It is better 
either to make up the stock solution without the hydrofluoric 
acid and add this just before use, or to omit the acid alto- 
gether, and use instead: 


Sodium fluoride 30 g 230 gr. 

or Potassium fluoride 44¢ 337 gr. 
Add just before use: 

Nitric acid 75 ccm 576 min. 


_ If the gelatine skin. is to be kept as a film, it should first be 
coated rather thickly with enamel collodion, made as follows: 


Pyroxyline 30 g 230 gr. 
Alcohol 500 ccm 8 oz. 
Ether 500 ccm 8 oz. 
Castor oil 20 ccm 154 min. 


Allow to dry thoroughly before applying the stripping fluid. 
In order to obviate the use of the fluorides, the following 
may also be used with success: . 
Potassium carbonate 100 g 770 gr. 


VARNISHES 159 


Formaldehyde 100 ccm 770 min. 
Glycerine 100 ccm 770 min. 
Denatured alcohol (meth. 

spirit ) 300 ccm 434 oz. 
Water to 1000 ccm 16 oz. 


The carbonate should be dissolved in the glycerine, and the 
water and other ingredients added. This solution is rather 
slower than the hydrofluoric acid; it can be used in a dish 
and allowed to act for 20 to 30 minutes. When the film 
proves to be loosened, pour off the solution, replace with a 
mixture of 4 parts of alcohol and 6 parts water, and leave 
for 5 to 10 minutes; then lift the plate out, drain, and strip 
the film as outlined above. 


Silver Printing Processes 


CoLLoDIO-CHLORIDE PRINTING-oUT EmMutsion.—The va- 
rious formulas have been calculated for a total bulk of 
1000 ccm (16 oz.). The correct method of making the emul- 
sion is to prepare the collodion by dissolving the pyroxyline 
in the alcohol and ether, by first pouring the former on to the 
pyroxyline and shaking until it is thoroughly saturated, and 
then adding the ether. Absolute alcohol should be used, and 
pure methyl alcohol may replace ordinary ethyl alcohol, but 
the alcohol must be free from pyridine bases, which cause dis- 
coloration of the coated paper. As little water as possible 
should be used to dissolve the chlorides, acid, and silver, and 
such solutions should be mixed with alcohol prior to addition 
to the collodion. It is often necessary to allow the raw col- 
lodion to stand for some time for any impurities or undis- 
solved fibers to settle down; but the best results are obtained 
with the specially prepared pyroxylines, sold under the name 
of celloidin or pyralin. The best chlorides are those of 
strontium and lithium, and only the crystalline salt of stron- 
tium should be used. The lithium chloride should be 
weighed out and dissolved in alcohol as soon as purchased, 
so as to make a 10 per cent solution, as it is very hygroscopic 
and absorbs varying quantities of moisture. These two 
chlorides are the most satisfactory in practice. Taking a 
typical formula (Hanneke), the following is the best method 
of mixing: 


Pyroxyline 26g 200 gr. 
Alcohol 565 ccm 9 oz. 
Ether 425 ccm 634 oz. 


160 


pIUVER PRINTING PROCESSES 161 


Add 500 ccm (8 oz.) alcohol to the pyroxylin, and shake well ; 
then add the ether. 


Lithium chloride, cryst. 3g 23 gr. 

Citric acid 5g SSin pr: 

Water 5 ccm 38 min. 
Dissolve by the aid of heat, and add: 

Alcohol 30 ccm 230 min. 


Then add to the collodion gradually with continual shaking, 
so as not to precipitate any of the pyroxyline: 


Silver nitrate 24¢ 184 gr. 

Water 30 ccm 230 min. 

Glycerine 7 ccm 54 min. 
Heat gently until the silver dissolves, and add: 

Alcohol 35 ccm 270 min. 


If any silver is thrown out in crystals, gently heat until dis- 
solved, and add gradually while hot in small quantities to the 
salted collodion, shaking well after each addition. Allow to 
stand to ripen, and then coat. The longer the emulsion stands, 
the faster the printing and the softer the gradation of the 
prints. The following formulas are those of the leading 
experimenters and should be compounded on the above lines. 
Niederstadt.— 


Pyroxyline 28 g PA Se: 
Alcohol 630 ccm 10 oz. 
Ether 350 ccm 534 oz. 
Citric acid 2.15 ¢g 16.5 gr. 
Lithium chloride, cryst. 2.15 ¢ 16.5 gr. 
Glycerine 7 ccm 54 min. 
Silver nitrate 20 g 154 er. 
Water 10 ccm 77 min. 
Geldmacher.— 
Pyroxyline 25g 192 gr. 


Alcohol 590 ccm 9% oz. 


162 PHOTOGRAPHIC FACTS AND FORMULAS 


Ether 400 ccm 6% oz. 
Citric acid 5g 38.5 gr. 
Strontium chloride, cryst. 5g 38.5 gr. 
Silver nitrate 20 g 154 er. 
Castor oil 4 ccm 31 min. 
Water 20 ccm 154 min. 


When castor oil is advised, which is used to keep the paper 
supple and prevent it from cracking, it should be mixed with 
an equal volume of alcohol before adding to the emulsion, 


and should be added last. 
Wall.— 


Pyroxyline 20 g 154 gr. 
Alcohol 535 ccm 84 oz. 
Ether 400 ccm 6%4 oz. 
Citric acid 2.5¢ 19 gr. 
Lithium citrate 2.5 19 gr. 
Lithium chloride, cryst. 2.5¢ 19 gr. 
Strontium chloride, cryst. 2.012 19 gr. 
Silver nitrate 20 g 154 gr. 
Water 20 ccm 154 min. 
Glycerine 1 ccm 8 min. 
M onckhoven.— 
Pyroxyline I5¢g l15.¢r. 
Alcohol 662 ccm 10 0z., 388 min. 
Ether 500 ccm 8 oz. 
Citric acid lig 8Y gr. 
Magnesium chloride, cryst. 3.1g 24 er. 
Silver nitrate 10g 77 gr. 
Water 10 ccm 77 min. 
Ammonia 0.6 ccm 5 min. 


Add the ammonia to the solution of citric acid. This was 
specially recommended for transparencies. 


SILVER PRINTING PROCESSES 


V alenta.— 
Pyroxyline 
Alcohol 
Ether 
Citric acid 
Lithium chloride, cryst. 


Strontium chloride, cryst. 


Silver nitrate 

Water 

Glycerine 
Beliteski.— 

Pyroxyline 

Alcohol 

Ether 

Citric acid 

Lithium chloride, dry 


Strontium chloride, cryst. 


Silver nitrate 
Water 
Glycerine 
V ollenbruch.— 
Pyroxyline 
Alcohol 
Ether 
Citric acid 
Lithium chloride, cryst. 


Strontium chloride, cryst. 


Silver nitrate 
Water 
Glycerine 
Anon.— 
Pyroxyline 
Alcohol 


20 g 
500 ccm 
500 ccm 

17g 

17g 
3.4¢ 
AES, 


20 ccm 
2 ccm 


tiie te 


600 ccm 
400 ccm 


222 
P25 ¢ 
3:40 2 
Zoe 
15 ccm 
20 ccm 


24 ¢ 
500 ccm 
500 ccm 

8g 
2g 
ites 

28 g 

34 ccm 
13 ccm 


8.33 g 
500 ccm 


154 gr. 
8 oz. 

8 oz. 
Laer. 
iSior: 
26 gr. 
58 gr. 
154 min. 
16 min. 


169 er. 
9 oz., 388 min. 
6% oz. 
169 gr. 
O14 gr. 
29 er. 
U/dier, 
115 min. 
154 min. 


184 gr. 

8 oz. 

8 oz. 

OZ Sr; 
15.5 or: 
31 gr. 
214.5 ger. 
260 min. 
100 min. 


65 gr. 
8 oz. 


163 


Ether 

Citric acid 

Calcium chloride, cryst. 
Silver nitrate 


Pyroxyline 
Alcohol 
Ether 

Citric acid 
Zinc chloride 
Silver nitrate 
Water 
Glycerine 


Bolton.— 


Pyroxyline 

Alcohol 

Ether 

Citric acid 

Lithium chloride, cryst. 
Silver nitrate 


Hanneke.— 


Pyroxyline 

Alcohol 

Ether 

Citric acid 

Calcium chloride, cryst. 
Silver nitrate 

Water 

Glycerine 

Castor oil 


Hanneke.— 


Pyroxyline 


500 ccm 8 oz. 
2.1¢g 16 gr. 
10.5 g 81 gr. 
35 g 269 gr. 
17.6¢ 135 gr. 
565 ccm 9 oz. 
424 ccm 7 OZ. 
1.3¢ 10 gr. 
3.6 g 27% gr. 
17.6¢ 135 gr. 
10 ccm 77 min. 
2 ccm 15 min. 
23 g 177 er 
490 ccm 7 0z., 400 min. 
490 ccm 7o0z., 400 min. 
4¢g Sligr: 
8g 62 gr. 
18g 138 gr. 
24.82 191 gr. 
540 ccm 814 oz. 
460 ccm 7% oz. 
5g 38 gr. 

4¢ 31 gr. 

25 2 192 gr. 

34 ccm 260 min. 
5 ccm 38 min. 

5 ccm 38 min. 
26 g 200 gr. 


164 PHOTOGRAPHIC FACTS AND FORMULAS 


Specially recommended for transparencies. 
Moss. — 


an i 


SILVER PRINTING PROCS SHS 


Alcohol 

Ether 

Citric acid 

Lithium chloride, cryst. 
Silver nitrate 

Water 

Glycerine 

Castor oil 


Hanneke.— 


Pyroxyline 

Alcohol 

Ether 

Citric acid 

Lithium chloride, cryst. 


Strontium chloride, cryst. 


Silver nitrate 
Water 
Glycerine 
Castor oil 


Hanneke.— 


Pyroxyline 

Alcohol 

Ether 

Citric acid 

Calcium chloride, cryst. 
Silver nitrate 

Water 

Glycerine 

Castor oil 


Pyroxyline 
Alcohol 


500 ccm 


30 ¢g 
500 ccm 


4 ccm 


This is intended for matt surface paper. 
Hanneke.— 


32g 
425 ccm 


8 oz. 
FiGz. 

38 er. 
ZO RT. 
185 gr. 
270 min. 
50 min. 
50 min. 


230 ger. 
8 oz. 
7% OZ. 
38 gr. 
15¥Y er. 
19 gr. 
184 er. 
274 min. 
46 min. 
46 min. 


185 gr. 
8 oz. 

7 OZ. 

38 er. 

31 gr. 
192 er. 
236 min. 
31 min. 
31 min. 


245 er. 
634 oz. 


165 


166 PHOTOGRAPHIC FACTS AND FORMULAS 


Ether 
Citric acid 


Calcium chloride, cryst. 


Silver nitrate 
Water 


575 ccm 


6.25 g 
6.25 g 
30 g 


20 ccm 


Specially suitable for transparencies. 


Cobenzl.— 
Pyroxyline 
Alcohol 
Ether 
Citric acid 


Lithium chloride, cryst. 


Ammonia 
Silver nitrate 
Glycerine 
Cobensl.— 
Pyroxyline 
Alcohol 
Ether 
Citric acid 


Lithium chloride, cryst. 


Ammonia 
Silver nitrate 
Water 


40 g 


500 ccm 
500 ccm 


4.75 ¢ 
ao 


5.5 ccm 


27 g 


10 ccm 


40 g 


500 ccm 
500 ccm 


6.62 g 
125¢ 


7.5ccm 


20 g 


10 ccm 


This is intended for matt surface paper. 


Sutton.— 
Pyroxyline 
Alcohol 
Ether 
Citric acid 
Lithium chloride, dry 
Silver nitrate 


40 ¢ 


500 ccm 
500 ccm 


13.3 g 
43¢ 
33.3 g 


9% oz. 
48 gr. 
48 gr. 

230 gr. 

154 min. 


307 gr. 
8 oz. 

8 oz. 
36 gr. 
Sir 
42 min. 
207 gr. 
77 min. 


307 gr. 
8 oz. 

8 oz. 
50 gr. 
OY gr. 
58 min. 
154 gr. 
77 min. 


307 gr. 
8 oz. 

8 oz. 
102 gr. 
33 gr. 
255 ‘er: 


SIeyoR PRINTING: PROCESSES 


Water 5 ccm 38 min. 
Castor oil 1 ccm 8 min. 
Krippendor ff.— 
Pyroxyline 21g 161 gr. 
Alcohol 600 ccm OY oz. 
Ether 400 ccm 6¥4 oz. 
Citric acid Bees 19 gr. 
Calcium chloride, cryst. tae ate 19 gr. 
_ Silver nitrate 2l¢g 161 gr. 
V alenta.— ; 
Pyroxyline 2202 165 gr. 
Alcohol 500 ccm 8 oz. 
Ether 500 ccm 8 oz. 
Citric acid 18g 138 gr. 
Calcium chloride, dry 14¢ 10 gr. 
Dissolve the above, and add: 
Silver nitrate 3g 2a or: 
Ammonia q. S. q.S. 


167 


Powder the silver, add just enough ammonia to form a clear 


solution, and add alcohol 30 ccm (230 min). Then add: 


Silver nitrate I5¢ 115 gr. 
Water 5 ccm 38 min. 
Glycerine 2.5 ccm 19 min. 
Alcohol 70 ccm 538 min. 


Dissolve by heat. This is specially suitable for platinum 


toning, and gives sepia prints without toning. 


Liesegang.— 
Pyroxyline 24¢ 184 gr. 
Alcohol 500 ccm 8 oz. 
Ether 500 ccm 8 oz. 
Lithium chloride, cryst. 3g 230%; 


Silver nitrate 24¢ 184 gr. 


Ashman.— 


Pyroxyline 

Alcohol 

Ether 

Citric acid 

Strontium chloride, cryst. 
Silver nitrate 
Cronenberg.— 
Pyroxyline 

Alcohol 

Ether 

Citric acid 

Lithium chloride, cryst. 


Strontium chloride, cryst. 


Silver nitrate 


Water 


Lainer.— 


Pyroxyline 

Alcohol 

Ether 

Citric acid 

Lithium chloride, cryst. 
Strontium chloride, cryst. 
Silver nitrate 

Water 

Castor oil 


Van Norath— 


Pyroxyline 

Alcohol 

Ether 

Citric acid 
Ammonium chloride 
Silver nitrate 


19g 
500 ccm 
500 ccm 
2.8¢ 
3.7 g 
19¢g 


25 ¢ 
600 ccm 
400 ccm 


20 g 
600 ccm 
400 ccm 


14.5 ¢g 
625 ccm 
325 ccm 

7a 
10g 
19g 


168 PHOTOGRAPHIC FACTS AND FORMULAS 


146 gr. 
8 oz. 

8 0z. 
22)4 gr. 
28%4 gr. 
146 gr. 


192 gr. 
OY, oz. 
6% oz. 
31 gr. 
15 gr. 
23 gr. 
154 gr. 
115 min. 


154 er. 
OY oz. 
634 oz. 
38 gr. 
19 gr. 
19 gr. 
154 gr. 
154 min. 
31 min. 


lilies 
10 oz. 
6 oz. 
55 er. 
77 St. 
146 gr. 


SieviER PRINTING PROCESSES 


Water 16 ccm 123 min. 
Glycerine 8 ccm 62 min. 
Eder.— 
Pyroxyline 21¢ 152 gr. 
Alcohol 600 ccm OY, oz. 
Ether 400 ccm 6% oz. 
Citric acid 5g 38 gr. 
Lithium chloride, cryst. peayeea 11.5 gr: 
Strontium chloride, cryst. 3g Zoot. 
Silver nitrate 14¢ 107% gr. 
Water 10 ccm 77 min. 
Glycerine 4 ccm 31 min. 
V alenta.— 
Pyroxyline 22.51 17 Sier, 
Alcohol 500 ccm 8 oz. 
Ether 500 ccm 8 oz. 
Citric acid 18g 138 er. 
Calcium chloride, cryst. 14¢ 10.7 gr. 
Silver nitrate 18¢ 138 gr. 
Water 10 ccm 77 min. 
Glycerine 2a cc 19 min. 


169 


FLATTENING.—Collodion papers when toned may need to 
be flattened by immersing them one by one face down in a 
smooth-bottomed tray containing a very little water. As 
soon as all are in, drain off the water and let the tray stand in 
a slanting position for ten minutes before toning. If this is 
not done, the prints may curl up badly. Subsequent manipu- 
lations are the same as for P. O. P. 

SILVER PHOSPHATE Paprer.—These are very rapid-printing 
papers with long scale of gradation. The phosphate emul- 
sions can be used alone or mixed with citro-chloride emulsions 
to increase the speed: 


170 PHOTOGRAPHIC FACTS AND FORMULAS 


Collodion, 4% 2100 ccm 334 oz. 

Ether 360 ccm 534 oz. 
Add: 

Phosphoric acid, sp. gr. 1.725 10ccm 77 min. 
Then add: 

Citric acid 80 g 614 min. 

Alcohol 140 ccm 21% 02. 
Shake well, and add: 

Silver nitrate 100 g 770 gr. 

Hot water 115 ccm 883 min. 

Alcohol 200 ccm 3% oz. 
Shake thoroughly, and add: 

Lithium carbonate 14.5¢ 111 gr. 
Till there is no longer any effervescence, and add: 

Glycerine 15 ccm 115 er. 

Alcohol 15 ccm 115 gr. 

Calcium chromate, 10% sol. 0.5 ccm 3.8 gr. 


This paper may be toned in the ordinary way or, if treated 
with 2.5 per cent solution of citric acid, till the yellow colour 
disappears and then washed, it gives rich brown tones on 
fixation in a hypo plus sulphite bath. Or the following may 
be used: 


Collodion, 314% 1960 ccm 31% oz. 

Phosphoric acid 9 ccm 69 min. 

Citric acid 772 591 er. 

Alcohol 130 ccm 998 min. 
Shake well, and add: 

Silver nitrate 100 g 770 gr. 

Ammonia q. Ss. q.S. 


Coarsely powder the silver, add very cautiously enough am- 
monia to form a clear solution, and add: 
Alcohol 320 ccm 5 oz. 


Sievoik PRINTING PROCESSES Til 


Add this in small quantities to the collodion, shaking thor- 
oughly after each addition, and add: 


Ether 320 ccm SIOZ. 
Glycerine 13 ccm 100 min. 
Alcohol 13 ccm 100 min. 


The addition of calcium chromate is not necessary with this 
emulsion, as it gives sufficiently brilliant prints without. This 
paper is specially suitable for very brief exposures and devel- 
opment with a metol-citric acid developer. 

SILVER BROMIDE PRINTING-oUT PAPER.—This gives a very 
rapid-printing paper with long scale of gradation: 


Citric acid 100 g 768 gr. 

Alcohol 400 ccm 6¥4 oz. 
Dissolve, and add: 

Collodion, 3% 5000 ccm 80 oz. 
Then add: 

Strontium bromide, anhydrous 16¢ 123 gr. 

Glycerine 20 ccm 154 min. 

Alcohol 30 ccm 230 min. 
After mixing, add: 

Silver nitrate 100 g 768 gr. 

Hot water q. S. q. Ss. 

Alcohol 400 ccm 6%4 oz. 


Dissolve the silver in as little water as possible, then add the 
alcohol, and add to the bromised collodion in small quantities, 
shaking well after each addition. Finally, add: 

Ether 800 ccm 13 oz. 
Allow the emulsion to stand a few minutes, and filter through 
glass wool. This emulsion must be mixed by orange light. 
It is about three times faster than commercial chloride papers 
and tones well in the usual baths, but is only suitable for 
contrasty negatives. The addition of calcium chromate gives 
more contrast. Even better results are obtained by replacing 


172 PHOTOGRAPHIC FACTS AND FORMULAS. 


some of the strontium bromide with anhydrous calcium 
chloride, thus using in the above: 

Strontium bromide, anhydrous 10.6 g 81.3 gr. 

Calcium chloride, anhydrous 3.3¢g 25.4 gr. 
If a still harder working paper is required, replace the calcium 
salt by uranyl chloride, 10 g (768 gr.). All these papers tone 
well in the usual baths, and lose but little in the fixing bath. 

Manipulation—The phosphate and bromide papers are 

used in the same way as ordinary printing-out papers. But, 
in consequence of their high sensitiveness, they should be 
manipulated in a yellow light, and extreme care should be 
taken when examining the prints during printing, otherwise 
a tint will be obtained over that portion of the paper exam- 
ined. They both tone well either in the separate or combined 
baths, but are specially suitable for sepia tones by platinum 
toning. 


Printing-Out Papers 


GELATINO-CHLORIDE OR PRINTING-OuT PAPER. — This 
paper, also called P. O. P. in England, is coated with an 
emulsion of silver chloride with an organic salt of silver and 
excess of silver nitrate in gelatine. The greater the ratio of 
organic salt, the more vigorous the prints. Many tormulas 
have been suggested, some of which either give poor results 
or the paper has poor keeping properties, and they are, there- 
fore, omitted. The following will be found reliable. 


Abney.— 

A. Sodium chloride 13.5¢ 104 gr. 
Citric acid 8.5 ¢ 65 gr. 
Potassium citrate eves 119 gr. 
Water 500 ccm 8 oz. 
Gelatine 54 ¢ 415 er. 

B. Silver nitrate 5l¢g 392 er. 
Water 400 ccm 6%4 oz. 

C. Chrome alum 0.6 g 4.5 gr. 
Water 100 ccm 14 oz. 


Soak the gelatine in the water for 30 minutes, melt at 50° C. 
(122° F.), and add B at the same temperature, stirring 
slowly; finally, add C. This gives a slow printing paper with 
very long scale of gradation and is most suitable for the 
combined bath. 


Barker.— 

A. Ammonium chloride Loe EPA Mg a 
Rochelle salts 59 ¢ 45.25 er. 
Citric acid 8.l¢g 62 gr. 
Alum l5g 115 ger. 
Gelatine 136 g 1044 gr. 


173 


174 PHOTOGRAPHIC FACTS AND FORMULAS 


Water 500 ccm 8 oz. 
B. Silver nitrate 322 245 gr. 
Water 500 ccm 8 oz. 


The gelatine should be equal parts of soft and hard. Mix 
as above. Vigorous printing, suitable for sulphocyanide and 
combined baths. 


Wade.— 

A. Ammonium chloride 24¢ 18.5 gr. 
Rochelle salts 24¢ 18.5 gr. 
Citric acid 15.6¢ 119.8 gr. 
Alum 5.2 g 40 er. 
Gelatine 32g 245 er. 
Water 500 ccm 8 oz. 

B. Silver nitrate 96 g 737 gr. 
Water 500 ccm 8 oz. 


_ Mix as above. Vigorous but rather slow printing, suitable 
for both baths. 


Beadle.— 

A. Ammonium chloride S.0c 26.9 gr. 
Rochelle salts 5g 38 gr. 
Citric acid 20 g 154 gr. 
Alum | be 38 gr. 
Water 500 ccm 8 oz. 

B. Silver nitrate Bho 288 gr. 
Water 500 ccm 8 oz. 


Mix as above. Vigorous and fast printing, suitable for both 
baths. 


Ashman.— 

A. Ammonium chloride 4.2¢ 4 Vane lea 
Tartaric acid 4¢ 30.7 gr. 
Sodium carbonate, cryst. q. Ss. q. Ss. 
Citric acid 5g 38 gr. 


Ammonium citrate I5¢g 115 gr. 


PRINTING-OUT PAPERS 175 


Gelatine 127 g 975 gr. 
Water 500 ccm 8 oz. 
B. Silver nitrate 30.6 g 235 gr. 
Water 500 ccm 8 oz. 


Dissolve the tartaric acid in a little water, and neutralise with 
sodium carbonate; then mix as above. Very fast and vigor- 
ous printing, and suitable for both baths. 


V alenta.— 

A. Amonium chloride 2.82 IAA 4 
Gelatine 96 g FRY! fae 
Water 750 ccm 12 oz. 

B. Tartaric acid 2.8¢ ZA oer, 
Sodium bicarbonate 14g 10.75 gr. 
Alum 18g - 13.8 gr. 
Water 125 ccm Zi0Z: 

C. Silver nitrate 32 g 245 gr. 
Water 125 ccm 21024 
Citric acid 8g 61 gr. 


Dissolve the tartaric acid and the alum in the water, and add 
the soda. Heat A and B to 50° C. (122° F.), and add C, 
heated to the same temperature, slowly with constant stirring. 
Vigorous, rapid printing, suitable for both baths. 

All the above emulsions can be made much faster printing 
by allowing them to stand about 1 hour at the mixing tem- 
perature before coating. These emulsions give glossy sur- 
faces, when coated on glossy baryta paper. If matt surface 
papers are required, the quantity of gelatine should be re- 
duced by about one-sixth, and a matt surface paper used for 
the raw stock. A very good matt surface can be obtained 
by the addition of an ammoniacal solution of pale yellow 
resin, made as follows: 

Ammonia 20 ccm 153 min. 


Water 80 cem 615 min. 


176 PHOTOGRAPHIC FACTS AND FORMULAS 


Add: 

Yellow resin 4g BLOT: 
Then heat the mixture until the resin is dissolved, adding 
more ammonia if necessary. Allow to cool, and add: 

Gelatine 4¢g Shor 

Water 40 ccm 307 min. 
Neutralise with hydrochloric acid, and add saturated solu- 
tion of citric acid until the mixture has a distinct acid reac- 
tion. This should be added to the emulsion, allowance being 
made for its bulk by reducing the quantity of water used in 
making up the emulsion. 

To obtain hard, contrasty printing papers, add to any of 
the above emulsions from 0.7 to 3.5 per cent of the following 
solution: 


Chromic acid 25 gS Gee 

Water 100 ccm 770 min. 
When dissolved, add: 

Calcium carbonate, pure q. Ss. 


with constant stirring until the mixture remains turbid, then 
filter, and wash the filter with: 

Water to make 250 ccm 4 oz. 
This forms approximately a 10 per cent solution of calcium 
chromate. The more of this is added to the emulsion, the 
harder it works. 

PRINTING should be carried on until the high lights show a 
decided tinge; then the prints should be immersed in: 


Salt 100 g 1! oz. 
Sodium carbonate, dry 50 g 34 02. 
Water 1000 ccm 16 oz. 


Bathe for 5 minutes, rinse for 5 minutes, and tone. 
TonincG may be effected either with an alkaline, a sulpho- 
cyanide, or a combined bath. The first-named does not give 


PRINTING-OUT PAPERS 177 


such satisfactory results as the others. The following are 
typical formulas: 


Chloride of gold lg FLEE bea 
Sodium acetate, or borax 30 g 230 gr. 
or Sodium tungstate or 
phosphate 10 ¢ (8h 
Boiling water 1000 ccm 16 oz. 
Or: 
Borax 20 g 154 ger. 
Sodium acetate 20 g 154 er. 
Boiling water 1000 ccm 16 oz. 
Or: 
Chloride of gold 0.25 ¢g 1.92 gr. 
Chalk Foe SA. er. 
Chloride of lime 0.75 g Be/ ok 
Water 1000 ccm 16 oz. 


For this bath the printing must be carried much further than 
usual, and the prints should be merely washed in water for 5 
minutes prior to toning. Or: 


Chloride of gold 2¢g TS er. 
Sodium bicarbonate 30 g 230 gr. 
Water | 1000 ccm 16 oz. 


This bath is very rapid in its action and gives blueish to 
violet-black tones, according to the depth of printing. An- 
other bath that gives very rich tones is: 


Chloride of gold 0.5¢ 3.8 gr. 
Sodium formate 60 g 460 er. 
Sodium carbonate 0.8 g 6 gr. 
Water 1000 ccm 16 oz. 


The sulphocyanide bath gives better tones, as a rule, than 
the above. A normal formula is: 
Chloride of gold 0.25 g Zor, 


178 PHOTOGRAPHIC FACTS AND FORMULAS 


Ammonium or potassium 
sulphocyanide 392 30 gr. 
Boiling water 1000 ccm 16 oz. 
Dissolve the gold in half the water, add to the sulphocyanide 
dissolved in the remainder, and use when cold. A very con- 
venient stock solution can be made as follows: 


Potassium sulphocyanide 24¢ 184 gr. 
Water 400 ccm 6Y4 oz. 


Heat to 98° C. (208° F.), and add slowly with constant 


stirring : 


Chloride of gold 8g 61 gr. 
Strontium chloride 80 g 614 gr. 
Water 400 ccm 6% oz. 


This should be heated to the same temperature. Allow to 
cool, filter, and wash the filter with: 
Water 200 ccm 2 oz. 

For use mix 1 part with 19 parts of water. The stock solu- 
tion must be kept in the dark. Sulphocyanide baths are 
rather apt to give double-toning, that is, blueish high lights 
with brown shadows. The following bath is free from this 
defect : 


Chloride of gold lg 77 gr. 
Salt 20 g 154 gr. 
Sodium sulphite, dry 0.5 ¢g 3.84 gr. 
Water 1000 ccm 16 oz. 


This should be allowed to stand for an hour before use. 
Red tones can also be obtained by the use of the following: 


Ammonium sulphocyanide 5g 38.5 gr. 
Potassium iodide 0.10to0.15¢ 0.8to 1.15 gr. 
Gold chloride Oi2are 1.92 gr. 
Water 1000 ccm 16 oz. 


Combined toning and fixing baths have found much favour, 
as the final tone is easily determined, which is not the case 


PRINTING-OUT PAPERS 179 


with the separate toning and fixing baths. An excellent 
formula and method of mixing was given by Valenta: 


Hypo 200 g 3% oz. 
Ammonium sulphocyanide 25 g 192 er. 
Lead nitrate 10g 77 st. 
Alum 20 g 154 gr. 
Water 500 ccm 8 oz. 


Dissolve the hypo in about three-fourths of the water, and 
add the sulphocyanide; then add the alum and lead nitrate 
dissolved in the remainder of the water. Heat the mixture 
to 50° C. (122° F.) for 10 minutes, allow to cool, and filter. 
For use, mix: 


Stock solution 500 ccm 8 oz. 
Water 500 ccm 8 oz. 
Gold chloride 0.8 g 6.1 gr. 


The prints must be well washed prior to toning. 

Fixinc.—The normal fixing bath, after any separate ton- 
ing bath, should be a 10 per cent solution of hypo, or an 
alkaline bath may be used, such as: 


Hypo 100 g LY oz. 
Sodium carbonate, dry 6.25 g 48 gr. 
Salt ig 96 gr. 
Water 1000 ccm 16 oz. 
Or: 
Hypo 100 g LY oz. 
Sodium sulphite, dry i232 96 gr. 
Salt 12.5¢ 96 gr. 
Water 1000 ccm 16 oz. 


Keep the prints moving in the fixing bath for 10 minutes, 
and then wash. Occasionally, a second fixing bath is used as 
conducing to greater permanency. 

The tone of the prints is to a great extent dependent on 
the quantity of gold per area, although this, naturally, varies 


180 PHOTOGRAPHIC FACTS AND FORMULAS 


with the character of the print, that is to say, the area of the 
dark parts of the image. The following will give a rough 
idea of the quantity of gold to be used for every 645 qcm 
(100 sq. in.): for red, 0.00324 g (0.05 gr.) ; for reddish- 
brown, 0.005 g (0.075 gr.) ; for brown, 0.0065 g (0.10 gr.) ; 
for warm purple-brown, 0.01 g (0.15 gr.) ; for cold purple- 
brown, 0.0125 g (0.19 gr. di for cold purple-black, 0.025 g 
(0.38 gr.). 

PLATINUM Toninc.—The tones obtained with gold range 
from reds to purples and browns. Colours ranging from 
sepia to black, without any trace of purple or red, are ob- 
tained with platinum as the toning agent. A suitable bath is: 


Potassium chloroplatinite 2g 15.4 gr. 
Dilute phosphoric acid 30 ccm 230 min. 
Water 1000 ccm 16 oz. 


The phosphoric acid may be replaced with dilute lactic acid, 
or acetic, tartaric, citric, oxalic acid in like quantity; or 
sulphuric acid, 10 ccm (77 min.), may be used. The above 
baths keep well and give pure whites. The following acts 
well when freshly prepared: 


Platinum perchloride 0.2¢ 1.54 gr. 
Sodium formate 6.3 ¢ 48 er. 
Formic acid 1.2 ccm 9.2 min. 
Water 1000 ccm 16 oz. 


The following is also an excellent bath (Valenta) : 
Potassium chloroplatinite O.5tolg 3.8to7.6 gr. 
Metaphenylendiamine O5tolg 3.8to7.6 gr. 
Water 1000 ccm 16 oz. 

For all platinum baths, the prints must be first immersed in 

a 10 per cent solution of common salt for 5 minutes, then 

rinsed; after toning, the prints should be immersed in: 
Salt 100 g 202, 
Sodium carbonate, dry 50 g 1 oz. 


PRINTING-OUT PAPERS 181 


Water 1000 ccm 20 oz. 
Bathe for 5 minutes, and then fix in 10 per cent solution of 
hypo. 

Namias.— 

Platinum perchloride tee 8.5 gr. 

Stannous chloride lg 7.7 gt. 

Water 50 ccm 1 oz. 


Dissolve the platinum in half the water, the tin salt in the 
remainder, and mix the two solutions; then add: 


Hydrochloric acid 5 ccm 384 min. 
Oxalic acid 10g 77 gr. 
Water to 1000 ccm 16 oz. 


The prints should be washed in salt and water, and then in 
plain water before toning. 

CoMBINED PLATINUM AND GoLp Toninc.—The use of 
gold and platinum gives pure black or blue-black tones, the 
blue tinge being dependent on the depth of toning with the 
gold. Print deeply, and immerse the print in: 


Salt 25 ¢g 192 gr. 
Sodium carbonate, dry Zoe 19 gr. 
Water 1000 ccm 16 oz. 
Leave for 5 minutes, wash well, and tone in: 
Borax 10g PML a 9 
Sodium acetate, fused 10g 77 gr. 
Gold chloride 0.5 ¢g 3.8 gr. 
Water 1000 ccm 16 oz. 
Then wash, and tone in: 
Potassium chloroplatinite 0.7 g 5.4 gr. 
Citric acid 10g ae 
Salt l6g 123 gr. 
Water 1000 ccm 16 oz. 


Tone until the prints look purple-black; then wash, and fix. 


182 PHOTOGRAPHIC FACTS AND FORMULAS 


Another process with a mercury salt, which is open to ques- 
tion as to permanency, is to tone with: 


Potassium chloroplatinite 3¢g 23 gr. 
Salt 20 g 154 gr. 
Water 1000 ccm 16 oz. 


Tone until a blue-violet colour is obtained; then rinse well, 
and tone again in: 


Mercury sulphocyanide 20 g 154 gr. 
Citric acid 20 g 154 gr. 
Gold chloride 3g 23 gr. 
Water 1000 ccm 16 oz. 


Wash well, and fix as usual. 
GoLp AND UrANniuM.—This also gives blackish prints: 


Gold chloride 0.25 g 1.9 gr. 
Uranium nitrate 0.25 g 1.9 gr. 
Salt 4¢g 31 gr. 
Sodium acetate 4g 31 gr. 
Water 1000 ccm 16 oz. 


Dissolve the gold and uranium, and add sufficient sodium 
carbonate to neutralise the solution; then add the other in- 
gredients. Printing must be rather deep; a salt bath should 
be used prior to toning, and an alkaline bath for fixing. 
Uranium Toninc.—This gives more or less red tones, 
the so-called red chalk or Bartolozzi colours. Print rather 
deeply, immerse in a salt bath, wash well, and tone in: 


Uranium nitrate VE 15.4 gr. 
Thiosinamine 10g 77 gr. 
Water 1000 ccm 16 oz. 


Wash thoroughly, and fix. 
PALLADIUM ToninGc.—This gives sepias and warm blacks 
but is not generally used. 
Potassium chloropalladite 0.5¢ 3.8 gr. 
Salt 32) Seer 


PRINTING-OUT PAPERS 183 


Sodium acetate 5¢g 38.5 gr. 
Water 1000 ccm 16 oz. 
Printing must be deep; the salt bath prior to toning, and the 

alkaline fixing bath must be used. 

DEVELOPING PRINTING-oUT Paper.—If a printing-out 
paper be exposed for a very short time, so that only a very 
faint image is visible, it is possible to develop it to full inten- 
sity. The first processes were practically physical intensifica- 
tion methods, based on the precipitation of the free silver 
nitrate in the emulsion on the image. As a rule, unpleasant 
greenish tones were obtained. A typical formula is: 


Gallic acid 5g 38.4 gr. 
Sodium acetate 10g 77 gr. 
Glacial acetic acid 10 ccm 77 min. 
Water 1000 ccm 16 oz. 


This should be diluted with from 5 to 10 parts of water 
before use. A more satisfactory result is obtained with the 
following: 


A. Hydrochinon 10g 77 gr. 
Alcohol 100 ccm 770 min. 
B. Sodium sulphite, dry 10g 77 gr. 
Citric acid lg 7.7 gr. 
Water 100 ccm 770 min. 


For use mix 5 parts each of A and B, and add 100 parts 
water. This works slowly, about 15 minutes being required 
for full development. The prints should be immersed in a 
5 per cent solution of salt after development, well washed, 
and then toned. Pyrocatechin gives more violet tones than 
the above; pyrogallol works much more quickly: 


Sodium sulphite, dry 50 ¢ 384 gr. 
Citric acid 10g 77 gr. 
Pyrogallol 10g 77 gr. 


Water 1000 ccm 16 oz. 


184. PHOTOGRAPHIC FACTS AND FORMULAS 


Paramidophenol may also be used (Hanneke) : 


Paramidophenol hydrochloride 7g 54 gr. 
Citric acid 8g 61 gr. 
Sodium sulphite, dry 25g 192 gr. 
Water 1000 ccm 16 oz. 
Liesegang’s aristogen for the same purpose was said to be: 
Hydrochinon 10¢g 77 gr. 
Sodium acetate 10g 77 gr. 
Citric acid 10g 77 gr. 
Sodium sulphite, sat. sol. 500 ccm 8 oz. 
Water 500 ccm 8 oz. 


It was discovered by Wilson that an alkaline developer could 
be used, if the print were first immersed in potassium bro- 
mide solution, so as to convert the whole of the silver salts 
into bromide. After exposure the print should be immersed, 
without washing, in a 10 per cent solution of potassium 
bromide for 5 to 10 minutes, then well washed, and treated 
with the following: 


A. Hydrochinon 18.2 g 140 gr. 
Sodium sulphite, dry 45¢ Rhea 
Sulphurous acid 9ccm 70 min. 
Potassium bromide 45¢ 35) or. 
Water 1000 ccm 16 oz. 

B. Caustic soda 9g 70 gr. 
Sodium sulphite, dry Og 70 gr. 
Water 1000 ccm 16 oz. 

C. Ammonium carbonate 36.5 g 280 gr. 
Ammonium bromide 36.5 g 280 gr. 
Water 1000 ccm 16 oz. 

Mix in equal parts before use. The following is simpler: 

A. Hydrochinon 22.8 ¢ 175 gr. 

Sodium sulphite, dry 114¢ 87.5 gr. 


Sulphurous acid 114¢ 87.5 gr. 


PRINTING-OUT PAPERS 185 


Water 1000 ccm 16 oz. 
B. Potassium bromide 62.5 g 1 oz. 
Ammonia 9 ccm 70 min. 
or Sodium carbonate, cryst. 45.5¢ 350 gr. 
Water 1000 ccm 16 oz. 


For use mix 1 part of each with 1 part water. Or the follow- 
ing may be used: 


A. Hydrochinon 3.65 g 28 gr. 
Sodium sulphite, dry 3.65 g 28 gr. 
Water 1000 ccm 16 oz. 


For use, mix 4 parts A, 4 parts B, given above, and 8 parts 
water. Greater contrasts can be obtained by decreasing A to 
3 parts, while flatter prints can be secured by increasing A to 
7 parts, the water in each case being increased or reduced, so 
as to make the total bulk of the solution the same. Another 
formula (Kodak) is the following: 


A. Hydrochinon 708 56 gr. 
Sodium sulphite, dry 3.65 g 28 gr. 
Potassium bromide 14.6 ¢ 112 gr. 
Ammonium bromide 29.2 ¢ 224 gr. 
Water 1000 ccm 16 oz. 

B. Caustic soda 62.5 ¢ 1 oz. 
Water 1000 ccm 16 oz. 

C. Tannin 16.6 g 128 gr. 
Water 1000 ccm 16 oz. 


For use mix 150 parts A, 30 parts B, 4 parts C. 
Whichever developer be used, it is important to observe the 
greatest care not to expose the paper to white light, as the 
slightest light action is developed. It is, therefore, advisable 
to manipulate the paper by yellow light entirely. The image 
should only be faintly visible after exposure. After the 
bromide bath, the prints should be washed at least 3 minutes. 
The developed image is a pale yellow or orange colour; care 


186 PHOTOGRAPHIC FACTS AND FORMULAS 


must be taken not to develop too far, and development should 
be stopped when the details in the high lights just begin to 
show. A stop bath of 10 per cent of potassium bromide or 
1 per cent glacial acetic acid should be used, the prints thor- 
oughly washed, and then toned in the ususal way. 

Disco (DEFENDER) PRINTING-OUT PAPER.—Print two or 
three shades darker than is desired in the final print. Wash 
in five or six changes of water before toning, and tone in the 
following, keeping the prints moving: 

Gold chloride solution 25 ccm 1 oz. 
Water 1000 ccm 40 oz. 
Add enough borax to turn red litmus paper blue. The above 
gold chloride solution is made by dissolving a 15-grain tube 
of gold chloride in 15 0z. or 425 ccm of water. When the 
desired tone is attained, transfer prints direct to a 4 per cent 

solution of hypo. 

EASTMAN SoLio PAPER.—Wash prints in 5 or 6 changes 
of water before toning. Tone in a plain gold bath, using 
044 ¢ (lgr.) to 1000ccm (480z.) water. Neutralise by 
adding a few drops at a time of saturated solution of borax, 
sodium bicarbonate or sal soda. Test with red litmus paper. 
When toned, immerse prints in running water, or: 


Common salt 8g 1 oz. 

Water 1000 ccm 128 oz. 
Fix not less than 10 minutes in: 

Hypo 100 g 13 oz. 

Water 1000 ccm 128 oz. 

Solio hardener 4 ccm Y, oz. 
The Solio hardener is made as follows: 

Aluminum chloride 250 ccm 3 02. 

Sodium bisulphite 208 g 2¥4 02. 

Water 1000 ccm 12 oz. 


Or the following may be used: 


PRINTING-OUT PAPERS 


Hypo 75 g 6 oz. 

Alum Score 2Y, 07. 

Sodium sulphite, dry 2g 80 gr. 

Water 1000 ccm 70 oz. 
When dissolved, add: 

Borax 9.5 g 34 OZ. 

Hot water 125 ccm 10 oz. 


This must be made 10 hours before use. 
CoMBINED BATH FoR SOLIO.— 


A. Hypo 90 g 8 oz. 
Alum 68 g 6 oz. 
Sugar 22.5 g 2 oz. 
Water 900 ccm 80 oz. 

Thoroughly dissolve in cold water, and add: 
Borax 22.5 ¢ 2 02. 
Water 100 ccm 8 oz. 
Allow to stand over night, and decant the clear liquid. 

B. Gold chloride 0.2 g 7% gr. 
Lead acetate l6¢ 64 gr. 
Water 100 ccm 8 oz. 


187 


This should be shaken up before use and not filtered. For 
use mix 1 part B with 8 parts A. Place prints in this without 
washing. Tone to the desired colour, and immerse prints for 
5 minutes in a stop bath of common salt, 1: 32; then give one 


change of water, and fix for 10 minutes in: 


Hypo 50 g 1 oz. 
Sodium sulphite, dry wo 30 gr. 
Borax 12.5 ¢ 4 oz. 
Water 1000 ccm 20 oz. 


Wash the prints for 1 hour in running water, or in 16 changes 
of cold water. The temperature of the combined bath should 


mov-exceed 10° C. (50° F.). 


Mimosa AurRoTyPE (SELF-TONING) PAPER.—Print much 


188 PHOTOGRAPHIC FACTS AND FORMULAS 


darker than the finished prints are required to be. Place, 
without washing, directly in the baths, which should be at 
18° C. (65° F.), and keep constantly in motion. 

For sepia tones: immerse for 10 minutes in a 10 per cent 
solution of hypo. 

For brownish-black tones: immerse for 10 minutes in a 
10 per cent solution of common salt; then transfer direct to 
the same strength hypo solution. 

For dark brown tones: immerse in: 


Hypo 100 g 2 oz. 
Salt 100g 5 2 oz. 
Water 1000 ccm 20 oz. 


Variation in tones from light to dark brown is obtained by 
decreasing or increasing the quantity of salt in the above bath. 
As soon as the desired tone is obtained, the prints should be 
carefully washed by repeated changes of water, or in run- 
ning water for 30 minutes. The most satisfactory method of 
drying is to place the prints between clean blotters. 

GEVAERT Ronix SELF-TonING Paper.—This is a collodio- 
chloride paper. Print a little darker than the finished print is 
desired to be. For sepia and brown tones, wash prints for 
three to five minutes in 2 or 3 changes of water, immersing 
them face down to prevent curling. Fix for 10 to 15 min- 
utes in: 

Hypo 100 g 2 02. 
Water 1000 ccm 20 oz. 
Wash for one hour, blot off surplus water, but do not dry 
between blotters. For dark brown and blue tones, wash as 

before and then immerse for 5 to 10 minutes in: 

Salt 100 g 2 ZOZs 
Water 1000 ccm 20 oz. 
Rinse, fix and wash as for sepia tones. Baths should be used 

only once, 


Salted Paper 


PLAIN oR SALTED Papers.—In this process the original 
surface of the paper is practically preserved, the sensitive 
salts being more or less in the fibers of the paper, in contra- 
distinction to those processes in which they are suspended 
in an emulsion. In all cases, however, a size should be used 
to prevent too deep penetration into the paper. Various 
sizes may be used; starches, such as arrowroot, etc., tend to 
give brownish tones, while gelatine tends rather to more 
blueish tones. The size may be applied to the paper first, 
but it is frequently more convenient to incorporate the salts 
with it: 

Arrowroot 20 g 154 ger. 
Water 750 ccm WATS 
Rub the arrowroot into a cream with a little of the water; 
bring the remainder of the water to the boil, add the arrow- 
root cream slowly with constant stirring, and continue heat- 

ing until a translucent liquid is formed. Then add: 


Ammonium chloride 14g0 107 gr. 
Sodium carbonate, cryst. 23 ¢ 177 gr. 
Citric acid 7g 54 gr. 
Water 250. ccm 4 oz. 


As effervescence takes place when mixing this latter solution, 
it is advisable to make it in a fairly large beaker before add- 
ing it to the arrowroot. It is as well, though not necessary, to 
boil this solution for 5 minutes to expel the carbonic acid. 
The salted arrowroot mixture should be strained through 
fine muslin while hot. Immerse the paper in the warm solu- 
tion for 2 minutes, and hang up to dry. When nearly dry, 
again immerse for the same time, and hang up by the oppo- 


189 


190 PHOTOGRAPHIC FACTS AND FORMULAS 


site corners to those previously used. As an alternative to 
this, the paper may be pinned by two corners to a flat board, 
and the salting solution freely applied with a broad flat brush. 
The solution is allowed to dry, and the operation is then re- 
peated. Increase of the arrowroot by 50 per cent increases 
brilliancy of the surface. For a gelatine size one of the 
following may be used: 


Gelatine 2¢g 15 gr. 
Ammonium chloride 18g 138 gr. 
Sodium citrate 18g 138 gr. 
Water 1000 ccm 16 oz. 
Or: 
Gelatine 4.5¢ 34 gr. 
Ammonium chloride 18 g 138 gr. 
Sodium citrate, dry 21.5¢ 165 gr. 
Salt 7g 54 gr. 
Water 1000 ccm 16 oz. 
Or: 
Gelatine 7g 54 gr. 
Ammonium chloride l4¢ 108 gr. 
Water 1000 ccm 16 oz. 


The more gelatine used, the higher the gloss of the resultant 
prints. The more citrate used, the more rapid the paper, with 
less contrast. Soak the gelatine in the water, melt by heat, 
and add the salts. 

MatTT AND SEMI-MATT Lac Papers.—With these bleached 
shellac with gelatine is used as a size. Unfortunately, 
bleached shellac is quite insoluble in aqueous mediums, and 
its solubility is very variable, unless freshly bleached: 


Bleached lac 83 g 637 gr. 
Borax 42¢ S23 26 
Water 750 ccm 12 oz. 


The lac should be broken up small, added to the borax solu- 


SAL TEDePAPIR 191 


tion, and the mixture boiled until it has dissolved, or not less 
than 2 hours, water being added from time to time to replace 
that which boils away. Then take: 


Bleached lac 50 g 384 gr. 
Sodium phosphate 25g 192 gr. 
Water 750 ccm 12 oz. 
Boil in the same way as above, mix the solutions, and add: 
Gelatine 46 g 353 gr. 
Water 500 ccm 8 02. 


Allow the gelatine to soak in the water for 30 minutes, and 
melt by heat. Filter the mixture through fine linen. Im- 
merse the paper for 2 minutes, and hang up to dry. When 
nearly dry, again immerse, and hang up by the opposite end. 
To salt this, float the paper on: 


Ammonium chloride 235 Vase 
Magnesium lactate 23 g 177 gr. 
Water 1000 ccm 16 oz. 


Then hang up to dry. Either the borax-lac or phosphate-lac 
may be used alone with half the above quantity of gelatine 
solution. 

All plain papers are most satisfactorily sensitised by brush- 
ing the silver solution on, not floating. Either a plain silver 
solution may be used, such as: 


Silver nitrate 62.5 g 1 oz. 

Water 500 ccm 8 oz. 
Or an acid one: 

Silver nitrate 732 560 gr. 

Citric acid Seo 400 er. 

Water 500 ccm 8 oz. 
Or an alkaline one: 

Silver nitrate oa 8 245 gr. 

Ammonia q. Ss. q. S. 


Water 250 ccm 4 oz. 


192 PHOTOGRAPHIC FACTS AND FORMULAS 


Dissolve the silver, add enough strong ammonia to form a 
clear solution, and then add: 

Silver nitrate 32 g 245 gr. 

Water 250 ccm 4 oz. 
If necessary add a little more ammonia to clear up any 
precipitate formed. Papers thus prepared will not keep more 
than a few hours, but they print very rapidly, and give very 
vigorous prints. It is better to use the plain silver solu- 
tions, and fume the paper with ammonia just before use. 
This can be effected by cutting the paper to size and pinning 
to the inside of the lid of a plate box, on the bottom of which 
is a sheet of blotting paper wet with a 10 per cent solution 
of ammonia. About 10 to 15 minutes will be sufficient. In- 
stead of the liquid ammonia, coarsely powdered ammonium 
carbonate may be used, and then the paper should be fumed 
for 30 minutes. 

Printing should be carried rather deep and the prints 
washed with repeated changes of water until no milkiness is 
seen in the water, or a 5 per cent solution of salt may be used, 
and the prints then washed for 10 minutes. Toning may be 
effected with either gold or platinum. Weak baths give the 
best results, such as: 


Borax 7zZ 54 gr. 
Gold chloride O.ll g 0.85 gr. 
Hot water 1000 ccm 16 oz. 


Sodium phosphate or acetate may be used instead of the 
borax, and the tones vary from sepia to purple, according to 
the duration of toning. As the prints always dry a little 
colder, or bluer, in tone than when wet, allowance should be 
made for this. A suitable platinum bath is: 

Potassium chloroplatinite 0.3 ¢ 2.3 et; 

Citric acid 8g 61 gr. 

Salt 2.5¢ 19 gr. 


See PAP ISR: 193 


Hot water 1000 ccm 16 oz. 
After toning, the prints should be immersed in a 1 per cent 
solution of common salt to stop the toning action, fixed in a 
5 per cent solution of hypo, and well washed. 

If resin-sized paper be used, the following will give black 
and sepia tones direct. For black tones: 


Sodium phosphate 40g 307 gr. 
Borax 20 g 154 gr. 
Sodium carbonate 10g 77 gr. 
Sodium chloride 5g 38.5 gr. 
Potassium bichromate 0.01 g 0.08 gr. 
Water ~ 1000 ccm 16 oz. 
For sepia tones: 
Sodium phosphate 20 g 154 gr. 
Borax 40 g 307 gr. 
Sodium chloride 5g Btn ed 
Potassium bichromate 0.08 g 0.6 gr. 
Water 1000 ccm 16 oz. 


Immerse the paper for 20 to 40 seconds, and dry. Sensitise 
on: 


Silver nitrate 50 g 384 gr. 
Lead nitrate 50 g 384 gr. 
Water 1000 ccm 16 oz. 


Neutralise this with sodium carbonate before use. 
The following method is given by Namias: 


Gelatine 2am 192 gr. 
Zinc chloride, cryst. 6g 46 er. 
Citric acid 5g 384 gr. 
Ammonia 6 ccm 46 min. 
Water 1000 ccm 16 oz. 


Soak the gelatine in half the water, and dissolve with heat; 
dissolve the acid in the remainder of the water, add the 
ammonia and then the zinc, mix the two solutions and filter. 


194 PHOTOGRAPHIC FACTS AND FORMULAS 


Tartaric acid may be used instead of the citric, and darker 


brown tones are obtained. 


Immerse the paper in the warm 


solution and dry. Sensitise by brushing over with either of 
the following solutions : 


Silver nitrate 120 g 922 gr. 
Citric acid 50 g 384 gr. 
Glycerine — 50 ccm 384 min. 
Water 1000 ccm 16 oz. 
Silver nitrate 120 g 922 gr. 
Ammonia q.s. q. S. 
Water 500 ccm 8 oz. 
Use enough ammonia to form a clear solution, and then add: 
Lactic acid, pure syrupy 50 ccm 384 min. 
Water to 1000 ccm 16 oz. 


Greater contrasts can be obtained by adding a little 5 per 
cent solution of potassium bichromate. A more rapid paper 
is obtained with the following: 


not keep: 


768 gr. 
384 gr. 
384 min. 
16 oz. 


512 gr. 
y Or 
12.3 gr. 


256 gr. 


Silver nitrate 100 g 
Uranium nitrate 50 ¢ 
Lactic acid 50 ccm 
Water 1000 ccm 
The following gives sepia tones, but the stock solution will 
Ammonio-citrate of iron, green 66.6 g 
Water 333 ccm 
Potassium bichromate 16g 
Dissolve, and add: 
Silver nitrate 33.3 g 
Water 667 ccm 


11 oz. 


After printing, this paper should be immersed in a 1 per cent 
solution of oxalic acid, then washed, and fixed in a 2 per cent 
hypo bath. 


pm oe 


eh ad LAMAN OAD aie aad 8 195 


A casein paper can be made as follows: 


Ammonium chloride 4¢ 31 gr. 

Sodium citrate, neutral 40 g 310 gr. 

Water 400 ccm 6 oz. 
Dissolve, and add: 

Casein 40 g 310 gr. 

Ammonia 50 g 384 min. 

Water 350 ccm 5Y4 oz. 
Warm this until dissolved, then add: 

Silver nitrate 70g 538 gr. 

Water to 1000 ccm 16 oz. 


This paper will not keep well, but can be made more stable 
by immersion in 3 per cent solution of citric acid. 
SENSITISING LEATHER, Fasrics, ETC. (Cobenzl).— 


Ammonium chloride 20 g 154 ger. 
Gelatine 5g 38 gr. 
Water 800 ccm 13 oz. 


Soak the gelatine in the water, add the chloride, melt with 
heat, and add to: 
Soluble starch 20 g 154 gr. 
Water 200 ccm ozs 
The material should be immersed in this until thoroughly 
soaked, then hung up to dry; if the fabric is thick and soaks 
up much of the liquid, more water should be added. When 
dry, it is silvered on: 


Silver nitrate 205¢ 30oz., 134 gr. 
Citric acid 103 g 791 gr. 
Water 1000 ccm 16 oz. 


The fabric should be laid on the bottom of a large dish, a 
glass rod placed on the top, the liquid poured over, and the 
rod rolled to and fro; this saturates the cloth without the 
necessity of touching it with the fingers. Artificial light 
should be used, and the drying should be as rapid as possible. 


196 PHOTOGRAPHIC FACTS AND FORMULAS 


After printing, the material should be immersed in salt 
solution, washed and toned as usual, if desired. 

Thin veneer wood can be sensitised; maple and plane give 
the best results; pear is less satisfactory. The wood should 
be immersed for at least 5 minutes in: 


Soft gelatine S72 288 gr. 
Water 1000 ccm 16 oz. 
Soak, melt by heat, and add: 
Formaldehyde 7.5 ccm 58 min. 
Dry with moderate heat, and immerse 5 minutes in: 
Hard gelatine 25¢g 192 gr. 
Soluble starch 100 g 768 gr. 
Ammonium chloride 10g 77 gr. 
Water 1000 ccm 16 oz. 
Again dry, and sensitise in: 
Silver nitrate 100 g 768 gr. 
Citric acid 83 g 637 gr. 
Water 1000 ccm 16 oz. 


Dry quickly. Print deeply from contrasty negan Ne wash 
and tone as usual. 

The sensitising of leather, such as split calfskin, is an easy 
matter, but it will not keep after sensitising. It is advisable 
to coat it first with plain collodion and then with a collodio- 
chloride emulsion. Or the following may be used: 


Hard gelatine 25.8 19 gr. 
Soluble starch 10g 77 gr. 
Potassium bromide 8.75 g 67 gr. 
Cadmium bromide 8.75 g 67 gr. 
Cadmium iodide 2.5¢ 19 gr. 
Ammonium chloride Pay 19 gr. 
Water 1000 ccm 16 oz. 
Saturate the material, dry quickly, and sensitise in: 
Silver nitrate 40 ¢ 307 gr. 


SALTED: PAPER 197 


Citric acid 50 g 384 er. 
Water 1000 ccm 16 oz. 
Clean brilliant negatives and short exposure to a bright light 
are required; enlargements may also be made. After expo- 
sure the material should be immersed in a 5 per cent solution 

of ammonium chloride, and developed with: 


Pyrogallol 20.8 19 gr. 
Hydrochinon Loc 58 gr. 
Citric acid 10g 77 gr. 
Sodium sulphite, dry 34 ¢ 260 gr. 
Water 1000 ccm 16 oz. 


Temperature 35° C. (95° F.). As soon as the image has well 
appeared, fix in an acid bath, and tone with gold. 

For an emulsion for fabrics, either of the following may 
be used: 


Hard gelatine 120 ga 2:0z., 40er: 

Water 1300 ccm Fale Riva 
Dissolve, and add: 

Zinc bromide, cryst. 43 g JL eT, 

Cadmium iodide lg f,/280: 

Cadmium chloride 3g 23 ot: 
mext, add at 70° C. (158° F.): 

Alcohol 500 ccm 8 oz. 
Then add in the darkroom: 

Silver nitrate 50 g 384 gr. 

Water 100 ccm 770 min. 
Finally, add: 

Alcohol 100 ccm 770 min. 


Digest for 2% hours at 80° C. (176° F.), and then cool 
down with constant stirring until the temperature is 15° C. 
(59° F.), when the emulsion will sink to the bottom of the 
vessel; this should be collected, washed, and melted with the 
addition of : 


Sodium carbonate 
Ammonium bromide 0.2 ¢ 


Water 2400 ccm 38 V, Oz. 


fe 


Melt at 30° C. (86° a and saturate the fabric. This = 





Bromide Paper 


ExposurE.—The most convenient light-source is an elec- 
tric incandescent lamp of comparatively low candle-power, 
not more than 16, otherwise the duration of exposure is so 
brief that serious errors may arise. It is preferable to have 
the light-source fitted with a push button, so that the light 
is only obtained while the button is pressed. This is handier 
than the usual form of switch. The light should be located 
as nearly as possible on a line with the center of the printing 
frame, and the end of the bulb should be towards the frame. 
The bench should be marked plainly with a scale of dis- 
tances, such as a yard measure, exactly parallel to the axial 
line of the light, and the frame should always be placed 
squarely at right angles to this scale. The exposures are 
practically as the squares of the distances between the light 
and the frame; that is to say, with a given light, negative, and 
paper, if the exposure at 12 inches is 5 seconds, it will be as 
12*: 24’ at 24 inches, or as 144:576, or 1:4. The thinner 
the negative, the greater should be the distance from the light. 
It is advisable not to select too short a distance, as the expo- 
sures are inconveniently short. The rule that the exposures 
are as the square of the distances is not strictly correct, for 
the light has less penetrative power at greater distances and 
will not pass through the denser parts of the negative. Slow 
papers give plucky results from flat negatives, and rapid 
papers give soft results from hard negatives. 

DEVELOPMENT.—Practically, the developers for bromide 
papers may be considered as half the strength of negative 
developers. Almost any reducing agent may be used, though 
pyro is the least suitable on account of its liability to stain 


199 


200 PHOTOGRAPHIC FACTS AND FORMULAS 


both gelatine and paper and its tendency to give rusty black 
tones. Amidol and metol-hydrochinon, also called M. Q., 
are the favourites; the former tends to give- blue-black, and 
the latter pure black tones. . 

Amidol.—This developer will not keep more than three 
days, and the most convenient method is to make up a 5 per 
cent solution of dry sodium sulphite, add 0.1 per cent of 
potassium bromide (% gr. to the ounce), add 0.8 per cent 
amidol (4 gr. to the ounce), and dilute with an equal bulk of 
water just before use: 


Sodium sulphite, dry . 34¢ | 260 gr. 
Potassium bromide 13 om 10 gr. 
Water 1000 ccm 16 oz. 
When dissolved, add: . 
Amidol 522 40gr. 
Metol-H ydrochinon.—The mean of the maker’s formulas 
is: 
Metol 3.5 g 27 gr. 
Hydrochinon 3g Zo Bie 
Sodium sulphite, dry 21g 1 AOR 
Sodium carbonate, dry l6g 123 gr. 
Potassium bromide los 10 gr. 
Water 1000 ccm 16 oz. 
Eastman Metol-hydrochinon Developer.— 

Elon (metol) 5g 4 oz. 
Sodium sulphite, dry 75g 74 02. 
Hydrochinon 20 g 2 oz. 
Sodium carbonate, dry 105 g 10% oz. 
Potassium bromide Pare i 120 gr. 
Wood alcohol 130 ccm 13 oz. 
Hot water 1000 ccm 100 oz. 


For use mix | part with 6 parts water. Temperature 21° C. 
(70° F.). 


* 


BROMIDE PAPER 201 


Eastman Amidol Developer.— 


Sodium sulphite, dry 120 g 14 oz. 
Acrol (amidol) 40 g Y o7z. 
Water 1000 ccm 12¥4 oz. 
For use mix: : 
Stock solution 157 ccm 1YZ oz. 
Potassium bromide, 10% sol. 1.7 ccm 8 drops 
Water 843 ccm 6 oz. 
Time of development should be not less than a minute and a 
quarter. 


GEVAERT ORTHOBROM AND NoVABROM BROMIDE PAPERS.— 
Developer for vigorous prints: 


a Dictol lg 8 gr. 
Hydrochinon Jog 28 ger. 
Sodium sulphite, cryst. 38 g 228 er. 
Sodium carbonate, cryst. 50 g 384 gr. 
Potassium bromide lg 8 gr. 
Water 1000 ccm 16 oz. 

For soft prints: 
Metol 5g 40 gr. 
Hydrochinon 15g 12 gr. 
Sodium sulphite, cryst. 62¢ 1 oz. 
Potassium carbonate 18.5 ¢ 150 gr. 
Potassium bromide lg 8 ger. 
Water 1000 cem 16 oz. 


Dissolve in order given. Prints of any required degree of 
vigour may be made by mixing the two solutions in suitable 
‘proportions. Development time, 3 minutes at 18° C. (65° 
fom F.). After rinsing, fix in: 
i “ - Hypo 250g 4 oz. 
. Potassium metabisulphite 25¢ 192 er. 
Water 1000 ccm 16 oz. 


202 PHOTOGRAPHIC FACTS AND FORMULAS 


Fix 10 minutes, wash 1 to 2 hours, and do not dry between 
blotters. 
HAMMER OPAL PLATES.— 


Metol 5g V4 oz. 
Hydrochinon 20 g Loz 
Sodium sulphite 75g 334 Oz. 
Sodium carbonate 125¢ 6% oz. 
Potassium bromide 1.25to25¢ ¥Y to ldr. 
Water 1000 ccm 50 oz. 


Add from 120 to 200ccm (6 to 100z.) wood alcohol to 
prevent precipitation. For use mix 1 part of above with 6 
parts water. 

FACTORIAL DEVELOPMENT FOR BroMIDE PAPER.—Dr. B. J. 
Glover puts forward a strong case for the application of the 
Watkin’s factorial system for bromide papers, which, how- 
ever, is not applicable to development papers on account of 
the very short time of appearance. The developer he adopts 
is the Kodak amidol formula at a temperature of 17° C., and 
he finds a remarkable coincidence between the exposure multi- 
plied by the time of development, in seconds, for prints 
showing practically the same result. This forms a constant, 
which is 1,800. Three cases are cited in which the exposures 
were 30, 15 and 10 seconds respectively and the factors 10, 
15 and 22% used. The results were practically indistinguish- 
able; and the total times of development were 60, 120 and 180 
seconds respectively, which, as will be seen, when multiplied 
by the exposures, equal 1,800. He formulates his first rule 
as follows: development must not be for a shorter time than 
that required to produce the maximum black of the paper. 
Accepting this, it will be obvious that it will be unnecessary to 
calculate both exposure and development; one only need be 
determined and the other is at once deduced therefrom, which 
practically forms his scond rule. As he puts it: a knowledge 


=o 


BROMIDE PAPER 203 


of either the correct exposure or the correct time of develop- 
ment is a complete guide to both exposure and development, 
since they are dependent variables in the sense that the pro- 
duct of one with the other is a constant quantity. The third 
rule is: the maximum development allowable is that which 
just stops short of fog or stain or both. Each developer has 
its own factor, which in the sense of the above rules varies 
within certain limits, these for the Kodak amidol being from 
10 to 30. As a mean 12 is convenient, and it is advisable to 
adopt this and make trial exposure strips. He lays down the 
axiom that the correct exposure for a bromide print is that 
which, when developed with any developer to an appropriate 
Watkin’s factor, yields a print of the desired depth. This 
is the only definition in existence, which has any value in 
practical work. 


Developing-Out Papers 


DEVELOPMENT OR GASLIGHT PApPERS.—These are com- 
paratively slow papers, which can be manipulated in not too 
bright a white light, though it is safer to use a yellow or 
bright orange safe-light. 

ExposurE.—The exposure is much longer than with bro- 
mide paper, and it is advisable to use a high candle-power in- 
candescent lamp, such as a 50-watt Mazda. The distance 
from the lamp should not be more than 12 inches. Or mag- 
nesium ribbon may be used, 1 inch at a distance of 12 inches 
being sufficient for an average negative for cold tones. The 
longer the exposure, with corresponding increase of bromide 
in the developer, the warmer the tones. 

DEVELOPMENT.—Any developer may be used, and, prac- 
tically, negative developers, with bromide, may be used full 


strength. 
Amidol.— 
Sodium sulphite, dry 32 g Y4 oz. 
Potassium bromide 0.13 g 1 gr. 
Water 1000 ccm 16 oz. 
When dissolved, add: 
Amidol hee 40 gr. 


For notes as to the keeping of this, see under Bromide Paper. 
Metol-Hydrochinon.—The mean of the maker’s formulas 
1S: 


Metol 19¢ 14¥4 gr. 
Hydrochinon 6.2:2 ae 47 gr. 
Sodium sulphite, dry 28 g 215 gr. 
Sodium carbonate, dry 4lg Slo on 
Potassium bromide 0.4¢ 3 gr. 


204 


DEVELOPING-OUT PAPERS 205 


Water 1000 ccm 16 oz. 
All formulas given under Bromide Paper are applicable to 
development papers. 

Non-ABRASION DEVELOPERS.—Glossy development papers 
are likely to show black hair-like lines, due to abrasion of the 
sensitive surface. The following has been suggested as 
obviating these: 


Metol 3.5¢g 27 gr. 
Hydrochinon 6g 46 gr. 
Sodium sulphite, dry 12¢ 92 gr. 
Sodium carbonate, dry 20 g 154 gr. 
Potassium bromide 0.4¢ Shae, 
Potassium iodide 2c 15.4 gr. 
Water 1000 ccm 16 oz. 


The iodide is the active agent and may be added in about the 

above ratio to any developer. Or add 0.156 per cent of hypo 

to the developer, that is, 1.56 g per liter (12 gr. per 16 0z.). 
Pyro DEVELOPER FOR WARM Brown TONES ON DEVELOP- 


MENT PAPERS.— 


A. Potassium metabisulphite 32 38.5 gr. 
Pyrogallol PEE 169 gr. 
Potassium bromide I5¢g 115 gr. 
Water 1000 ccm 16 oz. 

B. Sodium sulphite, dry 87.5 g 672 gr. 
Sodium carbonate, dry 87.5 g 672 gr. 
Water 1000 ccm 16 oz. 


For use mix A 10, B 20, water 70 parts. The image appears 
in from 30 to 40 seconds, and development is complete in 3 
or 4 minutes. The prints should be fixed in an acid bath 
without intermediate washing. 
ViTAvA (Kopaxk) PAPer.— 
1. Elon (metol) Oe 100 gr. 
Sodium sulphite, dry 100 g 31% oz. 


206 PHOTOGRAPHIC FACTS AND FORMULAS 


Hydrochinon 23 g 34 OZ. 
Sodium carbonate, dry 46g 1YZ oz. 
Potassium bromide SIVA 50 ger. 
Wood alcohol 138 ccm 414 oz. 
Water to 1000 ccm 32 oz. 
2. Sodium carbonate, dry 46¢ 14 oz. 
Water 1000 ccm 32 oz. 


In preparing No. 1, dissolve each chemical in three-fourths of 
the water, heated to about 53° C. (125° F.), before the next 
is added. Normal development should require from 1% to 2 
minutes. 

For Etching Brown, use: 125 ccm of No. 1, water to make 
1000 ccm, and add 7 ccm of 10 per cent solution of potassium 
bromide (20z. of No. 1, water to 160z., and 60 min. of 
potassium bromide solution). 

For Athena Old Master and Glossy, use: No. 1, 125 ccm, 
No. 2, 62.5 ccm, water to 1000 ccm, and add 3.5ccm of 10 
per cent solution potassium bromide (No. 1, 20z., No. 2, 
1 oz., water to 16 oz., and add 30 min. of potassium bromide 
solution). Temperature 21° C. (70° F). 


ARTURA.— 

1. Elon (metol) 6.5 ¢ 100 gr. 
Sodium sulphite, dry 100 g 3% oz. 
Hydrochinon 23 g 34 02. 
Sodium carbonate, dry 78g 2% oz. 
Potassium bromide 3.25 g 50 ger. 
Water to 1000 ccm 32 oz. 

Then add: 
Wood alcohol 138 ccm 41% oz. 

2. Elon (metol) 23.9 ¢ 34 OZ. 
Sodium sulphite, dry 100 g 3% oz. 
Potassium bromide 7a 8 150 gr. 
Water to 1000 ccm 32 oz. 


DEVELOPING-OUT PAPERS 207 


Then add: 
Wood alcohol 200 ccm 6¥4 oz. 
3. Sodium carbonate, dry 94 ¢ aera 
Water 1000 ccm D202; 


For normal developer for Artura Iris, use: No. 1, 125 ccm, 
potassium bromide, 10 per cent solution, 3.5ccm, water to 
1000 ccm (No. 1, 20z., bromide solution, 30 min., water to 
16 0z.). 

For soft developer for Artura Iris, use: No. 1, 62.5 ccm, 
a,2, 02.5 ccm, water to 1000 ccm (No. 1, 1 0z., No. 2, 1 oz., 
water to 16 0z.). 

For Artura Carbon Black or Carbon Green, use: No. 1, 
250 ccm, No. 3, 62.5ccm, potassium bromide, 10 per cent 
solution, 3.5ccm, water to 1000ccm (No. 1, 40z., No. 3, 
1 oz., bromide solution, 30 min., water to 16 0z.). 

For Non-Curling Film, use: No. 1, 250ccm, water to 
1000 ccm (No. 1, 40z., water to 160z.). Temperature of 
ai developers 21° C. (70° F.). 


Roylon Developer— 


Roylon Sg 24 er. 
Sodium sulphite, dry 23 ¢ 34 OZ. 
Hydrochinon 45¢ Aart, 
Sodium carbonate, dry 23 g 34, OZ. 
Potassium bromide, 10% sol. 10.5 ccm 90 min. 
Water to 1000 ccm 32 02. 


Suitable for all grades of Artura, except Carbon Black, for 
which there should be added 16 ccm of 10 per cent solution of 
potassium bromide to 1000ccm (% oz. to 160z.). 

Kodelon Developey—F¥or amateur use for Velox, Azo 
(and other developing papers) and bromide papers. Dis- 
solve in the order named: 

Water 1000 ccm 64 oz. 
Kodelon : 0.8¢ 25 gr. 


208 PHOTOGRAPHIC FACTS AND FORMULAS 


Hydrochinon Zo 90 gr. 
Sodium sulphite, dry 10.5¢ 330 gr. 
Sodium carbonate, dry 35 g 2% OZ. 


Add 2 drops of 10 per cent potassium bromide solution to 
each 30ccm (loz.) of developer. Use full strength at 
1S C65 RS); 

For professional use; soft developer for Artura Iris, Azo 
and other professional papers. Dissolve in order named: 


Water 1000 ccm 40 oz. 
Kodelon 0.5 ¢ 10 ger. 
Hydrochinon 2g 40 gr. 
Sodium sulphite, dry 9.5¢ 180 gr. 
Sodium carbonate, dry 03.9 180 gr. 


Add 1 drop of saturated solution of potassium bromide to 
each 60ccm (20z.) of developer. Use full strength at 
1S? CN Ome eye 

Tozol Developer —Stock solution for developing papers. 
Dissolve in the order named: 


Hot water 1000 ccm 30 oz. 
Tozol 33 1y Sie 1 oz. 
Sodium sulphite, dry 100 g 3 02. 
Sodium carbonate, dry 75g 2% oz. 
Potassium bromide Se 45 er. 
Wood alcohol 150 ¢g 414 oz. 


For portraiture on Artura and Azo use 100 ccm of stock 
solution to 700 ccm water (1 0z. to 7 02z.). 

For Velox, bromide, and amateur finishing grades of Azo, 
add 67 ccm (20z.) of dry sodium carbonate to the above 
quantity of stock solution and for use dilute 1 to 2 for Velox 
and Azo, and 1 to 6 for bromide papers. Use at 21° C. 
(Je rts 

HaLom PAPERS.— 

Metol 0.78 g 15 gr. 


DEVELOPING-OUT PAPERS 209 


Sodium sulphite, dry | Ras YZ oz. 
Hydrochinon 3.12 g 60 gr. 
Sodium carbonate, dry Laas Y, oz. 
Water 1000 ccm 40 oz. 


Add one drop saturated potassium bromide solution to every. 
2 oz. of developer (1 ccm to every liter). Times of develop- 
ment at 18° C. (65° F.): Portraya 1% to 2, Industro 1% to 
134, Rito % to 1%, Kalo 1 to 1%, Enlarging 1% to 1% 
minutes. The use of Kalo (slow speed) or Rito (fast speed) 
with the following developer gives cold, neutral or blue-black 
tones : 


Metol 5g Y, oz. 
Sodium sulphite, dry 75g 7 02. 
Hydrochinon 20 g 2 oz. 
Sodium carbonate, dry 125¢ 12Y4 oz. 
Potassium bromide _ 2¢g 100 gr. 
Hot water 1000 ccm 100 oz. 


For use mix 1 part stock solution with 3 parts water. 
Hatow Kato & Rito,—For neutral black tones: 


Metol 0.78 g 15 gr. 
Sodium sulphite, dry 12.5 ¢ YZ oz. 
Hydrochinon Bile, 60 gr. 
Sodium carbonate, dry pave 420 er. 
Water 1000 ccm 40 oz. 


Add one drop saturated solution potassium bromide to each 
two ounces of developer (1 ccm to every liter). 
Awnsco Cyko PaPER.— 


Metol 0.78 gr. 15 gr. 
Sodium sulphite, dry 25¢ 1 oz. 
Hydrochinon 3.12 g 60 er. 
Sodium carbonate, dry 18.75 g 34 Oz. 


Potassium bromide 0.26 g 5 gr. 


210 PHOTOGRAPHIC FACTS AND FORMULAS 


Water 1000 ccm 40 oz. 
Temperature 18° C. (65° F.). 
~ Ansco Noxo Parer.— 


Metol 0.78 gr. Laver: 
Hydrochinon 2.8¢ 60 gr. 
Sodium sulphite, dry 25g 1 oz. 
Sodium carbonate, dry 18.75 ¢ 34 OZ. 
Potassium bromide 0.376 g 8 gr. 
Water 1000 ccm 40 oz. 


Time of development 45 to 60 seconds. 
ENLARGING CyKo.— 


Metol 0.78 one 15 gr. 
Sodium sulphite, dry I2.5¢ Y, oz. 
Hydrochinon 3.122 60 gr. 
Sodium carbonate, dry 12.5 ¢ YZ oz. 
Potassium bromide, sat. sol. 1 to 3ccm 20 to 60 min. 
Warm water 1000 ccm 40 oz. 


Temperature 18° C. (65° F.). 
KopAk VELVET GREEN AND VELOX PAPERS.— 


Metol 0.5 g 7 gr. 
Sodium sulphite, dry 7g 110 gr. 
Hydrochinon 2g 30 gr. 
Sodium carbonate, dry 13 ¢g 150 gr. 
Potassium bromide, 10% 40 drops 40 drops 
Water 300 ccm 10 oz. 
Mimosa VEROTYPE PAPER.—For pure black tones, use: 
Sodium sulphite, cryst. 50 g 134 oz. 
Metol 2g 30 gr. 
Hydrochinon 6¢g O2 gt? 
Sodium carbonate, cryst. 135 ¢g 434 oz. 
Potassium bromide, 10% sol. 10 ccm 180 min. 
Water 1000 ccm 35 oz. 


Or the following separate solution developer : 





DEVELOPING-OUT PAPERS AMI 


A. Metol l4¢ 
Sodium sulphite, cryst. 140 g 
Water 1000 ccm 

B. Hydrochinon 17.5 ¢ 
Sodium sulphite, cryst. 100 g 
Water 1000 ccm 

C. Sodium carbonate, cryst. 150 g 
Hot water 1000 ccm 

D. Potassium carbonate 150 ¢ 
Water 1000 ccm 


216 gr. 
Biz. 
Ootoz. 
270 gr. 
3% oz. 
35 oz. 
514 02. 
35 oz. 
5% oz. 
JDO. 


For use mix as follows: for brown-black tones 1 part A, 1 
part B, 1 part C, and 3 parts water. By reducing B, a softer 
developer is obtained; by reducing A, a harder developer is 
obtained. For blue-black tones: mix 1 part A, 1 part B, 1 
part D and 3 parts water. To every 35 oz. of developer, add 
1% to 234 drams of 10 per cent solution of potassium 


bromide. 
Hydrochinon-S oda.— 
Sodium sulphite, cryst. 120 g 
Hydrochinon 24 g 
Sodium carbonate, cryst. 250 g 
Potassium bromide, 10% sol. 5 ccm 
Hot water 1000 ccm 


Time of development 1 minute. 
EASTMAN Azo PAPER.— 


Elon (metol) 6.25 g 
Sodium sulphite, dry 100 g 
Hydrochinon 25g 
Sodium carbonate, dry 72g 
Potassium bromide S2125.2 
Wood alcohol 150 ccm 
Hot water 1000 ccm 


414 oz. 

34 OZ. 

834 oz. 
114 drams 
So OF: 


60 gr. 
2 02. 
Y4 oz. 
1¥4 oz. 
30 gr. 
3 oz. 
20 oz. 


For use mix 2o0z. stock solution, water 140z., and add 


212 PHOTOGRAPHIC FACTS AND FORMULAS 


4 drops saturated solution potassium bromide. Temperature 
21° C. (70° F.). Prints must be exposed so that the time of 
development will be not less than 45 seconds for No. 1 or 
30 seconds for No. 2. For commercial and amateur print- 


ing, the following is recommended: 


Elon (metol) 0.73 g 7 gr. 
Sodium sulphite, dry l3¢ 110 gr. 
Hydrochinon 3.6 g 30 gr. 
Sodium carbonate, dry 18g 150 gr. 
Potassium bromide, sat. sol. 0.5 ccm 5 drops 
Hot water 1000 ccm 20 oz. 

emperature Zl Ge yOu rae 

DEFENDER COMMERCIAL PAPER.— 

Metol 0.77 g 15 gr. 
Sodium sulphite, dry 258 1 oz. 
Hydrochinon Sire 60 gr. 
Sodium carbonate, dry 18g VY oz. 
Potassium bromide, sat sol. 8 drops 10 drops 
Water 1000 ccm 40 oz. 

Temperature 18> Ce (Gaien). 

DEFENDER VELOUR BLAcK.— 

Metol 1.54 ¢ 30 gr. 
Sodium sulphite, dry 12.5¢ Y4 oz. 
Hydrochinon 4¢ 80 gr. 
Sodium carbonate, dry 12.5¢ YZ oz. 
Potassium bromide, sat. sol. 512 drops 600 drops 
Water 1000 ccm 40 oz. 

For commercial use: 
Metol lg 20 gr. 
Sodium sulphite, dry 12:52 YZ oz. 
Hydrochinon 3g 60 gr. 
Sodium carbonate, dry 18.75 g 34 OZ. 
Potassium bromide lg 20 gr. 





DEVELOPING-OUT PAPERS 213 


Water 1000 ccm 40 oz. 
DEFENDER PROFESSIONAL PAPER.— 

Metol O:// 2 15 gr. 
Sodium sulphite, dry 1a ie V4 oz. 
Hydrochinon 3g 60 gr. 
Sodium carbonate, dry P25 o 4 oz. 
Water 1000 ccm 40 oz. 
Potassium bromide, 

sat. sol. 25to 70 drops 30 to 80 drops 


The quantity of bromide determines the tone; with the small- 

est quantity a comparatively cold tone results with from 1 to 

114 minutes development for correctly exposed prints. 
Alternative developer for black and white prints: 


1. Metol 20 150 gr. 
Sodium sulphite, dry $3:3:2 502: 
Hydrochinon 8.3 ¢ 1% oz. 
Water 1000 ccm 150 oz. 

2. Sodium carbonate, dry 100 g 3 oz. 
Water 1000 ccm 30 oz. 

For use mix: 
Solution No. 1 312.5 ccm 10 oz. 
Solution No. 2 62.5 ccm 2 oz. 
Water 625 ccm 20 oz. 
Potassium bromide 2g O2ior. 


Develop from 1% to 3 minutes. Special stress is laid on the 
necessity of increasing the quantity of bromide with increase 
of the temperature of the developer. 

GEVAERT VITTEX (rapid gas-light paper).—For vigorous 
prints: 


A. Metol 0.9 ¢ Laer: 
Sodium sulphite, cryst. 35 g 1 oz. 
Hydrochinon 3:3ig 50 gr. 


Potassium carbonate, cryst. 70g 2 oz. 


214 PHOTOGRAPHIC FACTS AND FORMULAS 


Potassium bromide 0.5¢ 8 gr. 
Water 600 ccm 20 oz. 
Dissolve in order indicated. Development, 40 to 60 seconds 
atdton GO. (00 Ry: 

For soft prints: 


B. Metol 1.7¢g 25 of, 
Sodium sulphite, cryst. 28 g 34, OZ. 
Hydrochinon 0.5 g 8 gr. 
Potassium carbonate, cryst. fod 1 oz. 
Potassium bromide 0.5¢ 8 gr. 
Water 600 ccm 20 oz. 


Time and temperature as before. Prints of any desired 
vigour can be obtained by mixing A and B in appropriate 
proportions. After development, rinse and fix in: 


Hypo 250 g 5 oz. 
Water 1000 ccm 20 oz. 
Potassium metabisulphite 25¢ YZ oz. 


Fix for 10 minutes, wash one to two hours. Dry flat, but not 
between blotters. This paper gives warm black tones by 
simple development, and is not intended for sepia toning in 
sulphide solutions. 

GrEvVAERT Nova-cas (commercial gas-light paper ).— 


Metol lg 15 gr. 
Hydrochinon 4g 60 gr. 
Sodium sulphite, cryst. 35 g 1 oz. 
Sodium carbonate, cryst. 70g 2 oz. 
Potassium bromide, 10% sol. 30 to 60 drops 

Water 600 ccm 20 oz. 


Dissolve in order named. Develop at 18° C. (65° F.). If 
_ whites are not clean, add 15 drops 10 per cent solution of 
potassium bromide to each ounce (30 ccm) developer. After 
development, rinse. thoroughly and fix in: 

Hypo 150g 3 oz. 





DEVELOPING-OUT PAPERS ee Fs, 


Potassium metabisulphite 25g 4 oz. 
Water 1000 ccm 20 oz. 


Fix 10 to 15 minutes and wash 1 to 2 hours. 

SHort Stop BatuH.—For all developing papers it is advis- 
able to use a short stop bath. The prints should be rinsed as 
soon as sufficiently developed, and then immersed in: 


Acetic acid, 28% 47 ccm LY oz. 
Water 1000 ccm 32 oz. 


Use a fresh bath for each batch of prints, as the acid will 
become neutralized by the alkali from the developer. To 
reduce glacial acetic acid (9912%) to 28%, add 800 ccm of 
water to 300 ccm of the glacial acetic acid (8 oz. to 3 0z.). 


Toning Bromide and Gaslight Prints 


CoprperR Toninc.—Various shades from red to violet- 
brown are obtainable by this process, which is based on the 
deposition of red cuprous ferrocyanide on the image with the 
simultaneous formation of white silver ferrocyanide. It is 
actually an intensification process; therefore, the primary 
image must not be developed too far. 

Single solution (Ferguson) : 

Cupric sulphate, 10% sol. 106ccm 1 074.5 de, 


Potassium citrate, 10% sol. 800 ccm 13 oz. 
Potassium ferricyanide, 
10% sol. 94ccm. —10z:,3 dr, 


This solution will keep and does not stain plates or papers; 
the colours are dependent on the length of immersion. Sed- 
laczek gives the following formulas for various tones, and, 
as the baths will not keep well, they should be mixed just 
before use. In all these formulas, the quantities of the solu- 
tions should be added to the stated amount of water in the 
order given: 


Potassium citrate, 10% sol. 250 ccm 334 oz. 
Cupric sulphate, 10% sol. 40 ccm 290 min. 
Ammonia alum, sat. sol. 100 ccm LY, oz. 
Potassium ferricyanide, 
10% sol. 30 ccm 218 min. 
Water 750 ccm 12 oz. 
This gives red or violet-brown tones with clear whites. 
Ammonium oxalate, sat. sol. 200 ccm 3 02. 


Cupric sulphate, 10% sol. 40 ccm 290 min. 
Ammonium carbonate, 
10% sol. 10 ccm 72 min. 


216 





TONING BROMIDE PRINTS 217 


Potassium ferricyanide, 


10% sol. 30 ccm 218 min. 

Water 800 ccm 12 oz. 
This gives cherry red tones with a faint tinge in the whites. 

Potassium oxalate, 10% sol. 100 ccm 14 oz. 
Cupric sulphate, 10% sol. 40 ccm 288 min. 
Tartaric acid, 10% sol. 10 ccm 72 min. 
Potassium ferricyanide, 

10% sol. 30 ccm 216 min. 
Water 800 ccm 12 oz. 


This gives red-brown tones. The addition of 100 ccm (1% 
oz.) saturated solution of ammonia alum gives browner 
tones. 


Ammonium oxalate, sat. sol. 200 ccm 3 02. 
Cupric sulphate, 10% sol. 40ccm 288 min. 
Oxalic acid, sat. sol. 10 ccm 72 min. 
Potassium ferricyanide, 

10% sol. 30 ccm 216 min. 
Water 800 ccm T2002; 


This gives a reddish-violet tone. The following bath gives 
the so-called red chalk or Bartolozzi tones, but the whites 
are tinged: 
Ammonium carbonate, 
sat. sol. 570 ccm 8 oz. 
Cupric sulphate, 10% sol. 127 ccm 856 min. 
Potassium ferricyanide, 
10% sol. 304 ccm 5 oz. 
A weak ammonia bath, 1 per cent, will clear the whites. The 
following gives reddish-brown tones with clear whites (Crab- 
tree) : 
Cupric sulphate Ze, 92 pr, 
Potassium citrate 752g 576 gr. 
Ammonium carbonate 6g 46 gr. 


218 PHOTOGRAPHIC FACTS AND FORMULAS 


Potassium ferricyanide 12 ¢ 92 er, 
Water 1000 ccm 16 oz. 
With all the above baths much more transparent images may 
be obtained by immersion for about 5 minutes in a 5 per cent 
hypo solution. A violet-red tone is obtained (Somerville) by 
treating a copper-toned image with: 

Ammonia-iron alum, 


10% sol. 100 ccm 1 oz. 
Hydrochloric acid 10 ccm 72 min. 
Potassium bromide, 10% sol. 80 ccm 576 min. 
Water 1000 ccm 16 oz. 

Bleach the print in: 
Cupric sulphate 100 g 768 gr. 
Potassium bromide 100 g 768 gr. 
Water 1000 ccm 16 oz. 


Then immerse in a 2 per cent solution of nitric acid for 5 
minutes, wash well, and immerse in a 5 per cent solution of 
sodium sulphite, which gives a brown tone. 

Bleach the print in: 


Potassium ferricyanide 13.5¢ 104 gr. 
Potassium bromide Bien" 27 gr. 
Water 1000 ccm 16 oz. 
Wash for 10 minutes; then immerse for 1 minute in: 
Acid potassium oxalate __ 27 g 208 gr. 
Water 1000 ccm 16 oz. 


Then bathe for a few seconds in a 6 per cent solution of 
ammonia, and immerse in: 


Cupric sulphate 10g 7 é 200 
Hydrochloric acid 1.5 ccm 12 min. 
Water 1000 ccm 16 oz. 


Until the desired colour is obtained; then wash and fix. 
Immerse the prints in (Namias) : 
Rochelle salts 100 g 768 gr. 


si mia 


TONING BROMIDE PRINTS oie 


Cupric sulphate 10¢ 77 gr. 
Water 1000 ccm 16 oz. 
Potassium ferricyanide 5g 38 gr. 
Ammonia q. Ss. CaS: 


Add enough ammonia to form a clear solution. This gives 
violet tones. 

Uranium Toninc.—Treatment of a silver image with a 
mixture of a soluble uranium salt and ferricyanide of potas- 
sium results in brown to red images, the colour being de- 
pendent on the ratio of the two salts and the duration of 
toning. Intensification also takes place; therefore, the prints 
should not be too intense at first. The colour is dependent 
on the deposition of uranium ferrocyanide, which is soluble 
in alkalis. Long washing in ordinary water, therefore, will 
reduce the colour by dissolving the uranous salt. 

The following baths were recommended by Sedlaczek; all 
the quantities given represent the amount of 10 per cent 
solution that should be used, unless otherwise stated: 


Uranium nitrate 50 ccm 350 min. 
Ammonium oxalate 100 ccm 700 min. 
Hydrochloric acid 10 ccm 70 min. 
Potassium ferricyanide 20 ccm 140 min. 
Water 1000 ccm 16 oz. 
This gives brown tones. 
Uranium nitrate 50 ccm 350 min. 
Potassium oxalate 50 ccm 350 min. 
Hydrochloric acid 10 ccm 70 min. 
Potassium ferricyanide 20 ccm 140 min. 
Water 1000 ccm 16 oz. 


This gives warm brown tones. If a saturated solution of 
oxalic acid be used instead of the potassium oxalate, redder 
tones are obtained. 

Uranium nitrate | 50 ccm 350 min. 


220 PHOTOGRAPHIC FACTS AND FORMULAS 


Rochelle salts 70 ccm 490 min. 
Tartaric acid 100 ccm 700 min. 
Potassium ferricyanide 20 ccm 140 min. 
Water 1000 ccm 16 oz. 
This gives rich brown tones. 
Uranium nitrate 50 ccm 350 min. 
Rochelle salts 50 ccm 350 min. 
Ammonia alum, sat. sol. 100 ccm 700 min. 
Tartaric acid 50 ccm 350 min. 
Potassium ferricyanide .20 ccm 140 min. 
Water 1000 ccm 16 oz. 


This gives reddish-brown tones. 
A simpler formula is: 


A. Uranium nitrate 5g 38 gr. 
Water 500 ccm 8 oz. 
B. Potassium ferricyanide 5g 38 gr. 
Glacial acetic acid 14 ccm 96 min. 
Water 500 ccm 8 oz. 


Mix just before use. Or the prints may be immersed in 
B until bleached, well washed, and then soaked in A until the 
desired colour is obtained. In this last formula, the salts are 
dissolved as given; that is, 10 per cent solutions are not used. 

Olive green tones (Namias). Tone the prints in the usual 
uranium bath, then wash, and immerse in: 


Ferric chloride 5g 38.5 gr. 
Hydrochloric acid 10 ccm 77 min. 
Water 1000 ccm 16 oz. 


Fix in the acid hypo-sodium acetate bath. 

IRON oR CyAnoTyPE Toni1nc.—In this process the colour 
is dependent on the deposition of Prussian blue on the image, 
and this is soluble in alkalis; therefore, long washing in 
ordinary water is inadvisable. 

Immerse the prints in a 5 per cent solution of potassium 


TONING BROMIDE PRINTS 221 


ferricyanide with the addition of a little potassium oxalate, 
wash well, and treat with a 2 per cent solution of iron 
ammonium oxalate. This salt is the best to use for all iron 
toning baths, as it is stable and of uniform composition. 
Sedlaczek’s formulas are as follows, and all the quantities 
apply to 10 per cent solutions of the salts, unless otherwise 
stated : 


Ammonia iron alum 25 ccm 175 min. 
Potassium citrate 20 ccm 140 min. 
Ammonia alum, sat. sol. 100 ccm 700 min. 
Hydrochloric acid 5 ccm 35 min. 
Potassium ferricyanide 20 ccm 140 min. 
Water 1000 ccm 16 oz. 
This gives a deep blue tone. 
Ammonia iron alum 25 ccm 175 min. 
Potassium oxalate 60 ccm 440 min. 
Ammonia alum, sat. sol. 100 ccm 700 min. 
Hydrochloric acid 5 ccm 35 min. 
Potassium ferricyanide 20 ccm 240 min. 
Water 1000 ccm 16 oz. 


This gives a cold blue. If the hydrochloric acid and alum be 
omitted, and 10ccm (70 min.) of 10 per cent solution of 
tartaric acid be used, a grey blue colour is given. 


Ammonia iron alum 100 ccm 700 min. 
Potassium bromide 60 ccm 420 min. 
Hydrochloric acid 10 ccm 70 min. 
Water 1000 ccm 16 oz. 


This gives a bright blue. 

The following was specially recommended by Pfenninger 
for the blue constituent image in three-colour work. Im- 
merse the print or transparency in the following solution, 
made by weight: 

Potassium ferricyanide 30 g 230 er. 


222 PHOTOGRAPHIC FACTS AND FORMULAS 


Sodium carbonate, cryst. 10g fier: 
Ammonium nitrate 10¢ 77 gr. 
Salt 10 ¢g 71 at 
Water 1000 ccm 16 oz. 


The image bleaches to a bright greyish brown, and should be 
then well washed, and immersed in: 


Potassium bromide 5.0.8 42 er. 
Glacial acetic acid 16.5 ccm 127 min. 
Ammonium iron alum 5.51 42 gr. 
Water 1000 ccm 16 oz. 


As soon as the prints have assumed a steel blue colour, they 
should be well washed, fixed in a 5 per cent solution of hypo, 
again well washed, and immersed for 2 minutes in a 1 per 
cent solution of sulphuric acid. The prints should be rather 
darker than usual, as this process reduces the density slightly. 

VanapIuM ToninG.—This gives green tones which vary 
according to the ratio of iron to the vanadium salt and the 
duration of the washing. The colour is dependent on the 
deposition of vanadium ferrocyanide, which is yellow-orange, 
in combination with Prussian blue; with prolonged washing 
some of the latter dissolves; therefore, the green becomes 
brighter. Namias recommended separate baths: 


Potassium ferricyanide 50 g 384 gr. 
Water 1000 ccm 16 oz. 
Ammonia q.S. q. S. 


Add enough ammonia to make the solution smell distinctly 
after shaking well. Immerse the bleached and well washed 
prints in a bath compounded of the following stock solutions: 
A. Vanadium chloride, 2 per cent solution 
B. Ferric chloride, 2 per cent solution 
For use take: 
A solution 125 ccm 2 oz. 
B solution 125 ccm 2 oz. 


TONING BROMIDE PRINTS 223 


Water 1000 ccm 16 02. 
In the following, direct toning is used, a single bath being 
employed; the first is by Somerville: 


A. Ferric chloride 2:02 16 gr. 
Oxalic acid, sat. sol. 120 ccm Pio 
Vanadium chloride 462 Sait. 
Nitric acid 10.5 ccm 80 min. 
Water 500 ccm 8 oz. 

B. Potassium ferricyanide 2:3 g 16 gr. 
Water 500 ccm 8 oz. 


Mix just before use. Duration of toning 2 to 4 minutes; 
wash and fix in: 


Hypo 200 g SOR 
Boric acid 40 ¢ 200 gr. 
Water 1000 ccm 10 oz. 


Finally, wash for 10 minutes. 

The disadvantage of the above baths is that some opaque 
silver chloride is formed, so that the results are somewhat 
muddy and control of the colour is not easy. By using 
vanadium oxalate or sulphate, much brighter colours and 
clearer prints are obtained (Wall). It is necessary to make 
these salts, but this is an easy task: 


Ammonium metavanadate LOO ours oz, ASO or. 
Oxalic acid, pure 460 gers 1b: 
Water 500 ccm 17 oz. 


Mix into a cream in a beaker or porcelain dish, and heat 
gradually with constant stirring. Solution gradually takes 
place, and the colour turns to orange and greyish-blue, but, 
as the heat is continued, it becomes a bright blue. Finally, 
add water until the bulk measures 1477 ccm (520z.). If 
the sulphate is to be used, although it presents no advantages, 
use: 
Ammonium metavanadate 100g 30o0z., 130¢r. 


224 PHOTOGRAPHIC FACTS AND FORMULAS 


Water 500 ccm 174 oz. 
Mix into a cream and add slowly with constant stirring pure 
sulphuric acid, sp. gr. 1,845, 70 ccm (1183 min) ; then follow 
the directions given above. The actual toning bath is: 

Ammonium oxalate or sulphate 


solution as above 50 ccm 384 min. 
Oxalic acid, sat. sol. 50 ccm 384 min. 
Ammonia alum, sat. sol. 50 ccm 384 min. 
Ferric oxalate, 20% sol. q. Ss. q. Ss. 
Glycerine 50 ccm 384 min. 
Potassium ferricyanide, 

10% sol. 10 ccm 77 min. 
Water 1000 ccm 16 oz. 


Mix the oxalic acid and vanadium solutions with half the 
water; then add the alum solution and the ferric oxalate; 
mix the ferricyanide solution with the glycerine and the 
remainder of the water, and add to the first solution. The 
more ferric oxalate used, the bluer the colour; with 10 ccm 
(77 min.) in the above bath a bright emerald green tone is 
obtained. Toning takes from 10 to 15 minutes; the prints 
should be immersed in a 10 per cent solution of sodium 
sulphate for 5 minutes, and then washed for 10 minutes. 

Namias suggests the following method of making van- 
adium chloride: 


Ammonium vanadate 100 g 768 gr. 
Hydrochloric acid 250 ccm 4 oz. 
Water 250 ccm 4 oz. 


Sodium bisulphite, dry 60 to 80g 460 to 610 gr. 
Heat until the solution turns blue and dilute to 1000 ccm 
(16 oz.) with water. For green tones bleach the prints in the 
usual ferricyanide bath, wash well, and immerse in: 

Vanadium chloride, as above 25 ccm 192 min. 

Ferric chloride 2.5¢g 19 gr. 


TONING BROMIDE PRINTS 225 


Ammonium chloride 100 g 768 gr. 
Water 1000 ccm 16 oz. 
More ferric chloride gives bluer tones. Wash and fix in an 

acid-hypo sodium acetate bath. 

Leap Toninc.—Various colours may be obtained by 
bleaching prints with a lead salt and ferricyanide, and sub- 
sequent treatment with various reagents. The results are not 
very satisfactory; there is a very great tendency for the 
whites to be stained, and great intensification is given. The 
bleaching bath may be: 


Lead acetate or nitrate 40g 307 gr. 
Glacial acetic acid 100 ccm 770 gr. 
Potassium ferricyanide 60 g 460 gr. 
Water 1000 ccm 16 oz. 


When thoroughly bleached, the prints should be washed with 
three successive baths of 10 per cent nitric acid, then washed 
for a short time with water, and treated with one of the 
following baths: ammonium sulphide, 1:3, for black; 
Schlippe’s salt, 2 per cent solution, for reddish-yellow; 
potassium chromate, 2 per cent, for yellow; ferric chloride 
for green; cupric chloride for red; uranium nitrate and 
ammonium chloride for red-brown; cobalt or nickel chloride 
for green; mercuric iodide for orange-yellow. 

Lead-tron for greenish tones (Maquenne ).—This is a com- 
plicated process, which is open to the same objections as 
above, but the prints must be rather denser than normal, as 
there is no intensification. Four stock solutions are required, 
which will keep in the dark: 


A. Lead acetate 135 ¢ 1036 gr. 
Glacial acetic acid 100 ccm 768 min. 
Ferric chloride, dry I5¢ 115 gr. 
Water 1000 ccm 16 oz. 


B. Lead acetate 100 g 768 gr. 


226 PHOTOGRAPHIC FACTS AND FORMULAS 


Glacial acetic acid 100 g 768 gr. 
Water 1000 ccm 16 oz. 
C. Potassium ferricyanide 100 g 768 gr. 
Water 1000 ccm 16 oz. 
D. Ferric chloride L7ae: 13.4 gr. 
Glacial acetic acid 10 ccm 77 min. 
Water 1000 ccm 16 oz. 


To make A, dissolve the lead salt in the acid and water, add 
the iron, shake well, and filter. Blue-green tones are obtained 
by immersion of the prints for 5 minutes in a 2 per cent 
solution of glacial acetic acid and then in the following for 
6 minutes : 


A solution 100 ccm 1 oz. 
C solution 100 ccm 1 oz. 
Water 1000 ccm 10 oz. 


Again immerse in the dilute acetic acid bath for a short time, 
wash well, transfer to a 0.5 per cent solution of citric acid, 
and wash for an hour. Then rub the surface gently with a 
pad of absorbent cotton, and immerse in: 
Potassium chromate 5tol0g 38to/77 gr. 
Water 1000 ccm 16 oz. 
The colour turns brownish-green; wash the prints, immerse 
in the citric acid solution, as above, and wash for a short 
time. Bright green tones are obtained by preliminary treat- 
ment with an acetic acid bath and immersion in: 


A solution 80 ccm 614 min. 
B solution 20 ccm 154 min. 
C solution 100 ccm 768 min. 
Water 1000 ccm 16 oz. 


Then the prints must be treated with the acetic acid, chromate 
and citric acid baths. Pure green tones are obtained by 
treating the prints to a preliminary acid bath, then im- 
mersing in: 


TONING BROMIDE PRINTS jolla 


B solution 50 ccm 384 min. 
C solution 50 ccm 384 min. 
Water 1000 ccm 16 oz. 


Without washing, transfer to the first bath given for blue- 
green. Rinse well and transfer to solution D. Treat with 
the dilute acid baths, wash well, and dry. 

Green tones can also be obtained (Sedlaczek) by bleaching 


the prints in: 


Lead nitrate l5¢g 115 gr. 
Nitric acid 10 ccm 77 min. 
Potassium ferricyanide lg eet: 
Water 1000 ccm 16 oz. 
Wash well, and immerse in: 
Ammonia iron alum 100 g 770 gr. 
Potassium bichromate, sat. sol. 50 ccm 385 min. 
Potassium bromide Sig 38 gr. 
Water | 1000 ccm 16 oz. 


Treat the prints with a 3 per cent solution of hydrochloric 
acid until the whites are clean. Brighter green tones are 
obtained by immersion of the lead-bleached image in a 0.5 
per cent solution of potassium bichromate, rinsing, and then 
treating with the above iron alum bath. Or blue-green tones 
may be obtained by using the following instead of the iron’ 


bath: 


Ammonia iron alum 100 g 770 gr. 
Potassium bromide 50 g 385 gr. 
Water 1000 ccm 16 oz. 


Uranium AND Iron Tonine (Blake-Smith).—This also 
gives blueish-green tones: 


Uranium nitrate og 38.5 gr. 
Ammonio-citrate of iron 5g 38.5 gr. 
Nitric acid 5g 38.5 gr. 


Potassium ferricyanide 10g 77 gr. 


228 PHOTOGRAPHIC FACTS AND FORMULAS 


Water 1000 ccm 16 oz. 
Or the following (Eder) : 

Uranium nitrate 5g 38.5 gr. 

Ammonio-citrate or iron 5g 38.5 gr. 

Glacial acetic acid 200 ccm 314 02. 

Water 1000 ccm 16 oz. 


CosaLt Tonine (Somerville) —Greenish or green-blue 
tones are obtained by this process, but they are very unsatis- 
factory. Bleach the image in: 


Potassium bichromate 60 g 460 gr. 
Potassium ferricyanide 300 g 5% oz. 
Water 1000 ccm 16 oz. 
Then wash until free from any yellow stain, and immerse in: 
Cobalt chloride 25 g 192 gr. 
Ferrous sulphate 6g 46 er. 
Hydrochloric acid 200 ccm 314 oz. 
Water 1000 ccm 16 oz. 


Replacement of the hydrochloric by glacial acetic acid gives 
brighter green tones. The prints should be fixed in: 


Hypo 250 g 4 oz. 
Boric acid 45 ¢ 345 gr. 
Water 1000 ccm 16 oz. 


Dissolve by heat, and use when cold. Wash the prints well. 
Or bleach the image in: 


Potassium ferricyanide 60 g 460 gr. 

Lead nitrate 40 ¢ 307 gr. 

Water 1000 ccm 16 oz. 
Wash thoroughly, and immerse in: 

Cobalt chloride 100 g 768 gr. 

Hydrochloric acid 30 ccm 230 min. 

Water 1000 ccm 16 oz. 


Gotp AND PLatinum Tonine (Somerville) —Gold toning 
is sometimes resorted to, more to improve the colour of prints 


TONING BROMIDE PRINTS TAS, 


than to obtain warm tones; and greenish or rusty prints can 
be improved by placing them face up, as they come from the 
washing after fixing, on a sheet of glass, dabbing into flatness 
with a clean pad of linen, and brushing over with: 


Ammonium sulphocyanide 20 g 154 gr. 
Gold chloride lg FETT 
Hot water 1000 ccm 16 oz. | 


Use when cold. A soft flat brush, without metal binding, 
should be used. When the desired improvement is reached, 
that is, when the image becomes black or blue-black, wash 
well, and dry. Purple blacks can be obtained by bleaching 
the prints first in: 


Cupric sulphate 25 ¢g 192 gr. 
Potassium bromide 2g 192 gr. 
Water 1000 ccm 16 oz. 


Rinse, and immerse for 5 minutes in 5 per cent nitric acid, 
wash, and tone in: 


Ammonium sulphocyanide 8g 61 gr. 
Ammonia 3 ccm 23 min. 
Gold chloride Ze 18 gr. 
Water 1000 ccm 16 oz. 


Toning takes from 10 to 20 minutes, and the more ammonia 
used, the deeper the tone. 

Platinum toning gives warm sepias, but the results are not 
permanent. The following may be used (Heatherly) : 


Potassium oxalate 160 g 1228 gr. 

Mercuric chloride 13g 100 gr. 

Potassium citrate 20 g 154 gr. 

Citric acid 40 g 307 gr. 

Water 1000 ccm 16 oz. 
Mix, and add just before use: 

Potassium chloroplatinite ZA 20.7 gr. 


Hydrochloric acid 2.7 ccm 21 min. 


230 PHOTOGRAPHIC FACTS AND FORMULAS 


Water 1000 ccm 16 oz. 
When the desired tone is obtained, wash well, and dry; 
slightly darker tones are obtained if the print is immersed in 
a 2 per cent solution of sodium carbonate. 

The following is stated to be suitable for bromide but not 
development (gaslight) prints: 


Mercuric chloride 2g 16 gr. 
Potassium chloroplatinite 4¢g 32 gr. 
Citric acid 18g 138 gr. 
Water 1000 ccm 16 oz. 


This should be made up fresh, and gives warm sepias with 
slight staining of the high lights. For cold sepia tones, with 
absence of staining of the whites, add potassium bromide 
lg (8gr.) to the above. Wash well after toning. 

SELENIUM Toninc.—This gives various shades of sepia 
to purplish-red tones (Miliani) : 


Powdered selenium 2tol0g 154to/77 gr. 
Sodium sulphide 100 g 768 gr. 
Water 1000 ccm 16 oz. 


Heat the solution till the selenium dissolves, and dilute as 
required for use. The weaker the bath, the more sepia the 
colour. On diluting the bath, some selenium is thrown down, 
and the solution should be filtered, or the prints after toning 
passed through two or three baths of 1 per cent solution of 
sodium sulphide. Another (Valenta) : | 


Selenium 16.5 ¢ 127 gr. 
Sodium sulphide 200 g 3 1/5 oz. 
Water 1000 ccm 16 oz. 


Heat until dissolved, dilute with 5 to 6 times the volume of 
water, and add pyrocatechin, 1 per cent solution, 20 to 40 ccm 
to every liter or 154 to 307 min. to 160z. If the whites are 
tinged, pass the prints through weak baths of acid sulphite 
of soda. 


TONING BROMIDE PRINTS Zo 


According to Mimosa, if the selenium bath be neutralised 
with boric acid, there is no precipitation of the selenium; the 
addition of ammonia reduces the staining of the whites, which 
may be removed by a 10 per cent solution of potassium 
metabisulphite. | 

Namias recommends to fuse in a nickel or iron crucible 
2 parts of granular selenium with 10 to 15 parts of caustic 
soda, and, when cold, dissolve in 100 parts of water. The 
toning bath is: 


Sodium selenide, thus made 100 ccm 768 min. 
Sodium sulphide 50 g 384 gr. 
Water 1000 ccm 16 oz. 


Bleach the prints in the usual way, and then tone in this 
solution. A combined toning and fixing bath may be pre- 
pared by mixing: 


Hypo 66 g 500 gr. 
Sodium selenide,asabove afewdrops afewdrops 
Water 1000 ccm 16 oz. 
Boric acid 40g 307 gr. 


Dissolve the hypo and the acid in hot water, and add the 
selenium solution when cold. Better sepia tones are obtained 
with the following: 
Powdered selenium 2 parts 
Sodium sulphide 50 parts 
Fuse together and dissolve in 150 parts of water. To make 
the bath, add a few drops of this stock solution to a 2 per cent 
solution of sodium sulphide. All selenium salts have an 
intense garlic odor, which is very lasting. 
MotyspeNuM TonincG (Namias).—This gives a deep blue 
tone: 
Molybdic acid 100 g 2 02. 
Ammonia 250 ccm 50%: 
Water 250 ccm 5 oz. 


232 PHOTOGRAPHIC FACTS AND FORMULAS 


When dissolved, pour into: 


Nitric acid 500 ccm 10 oz. 

Water 500 ccm 10 oz. 
To make the bath use: 

Molybdate solution above 250 ccm 4 oz. 

Water 1000 ccm 16 oz. 

Potassium metabisulphite 50 g 384 er. 


This should be used in artificial light, and the prints well 
washed. 

TONING BY REDEVELOPMENT (Manly).—Various tones can 
be obtained by bleaching prints with the following baths and 
redeveloping with the given developers: 


A. Potassium ferricyanide 33 g 250 gr. 
Ammonium bromide 40 g 310 er. 
Water 1000 ccm 16 oz. 

B. Cupric sulphate 50 g 384 gr. 
Sulphuric acid 6.5 ccm 50 min. 
Common salt 50 g 384 gr. 

| Water 1000 ccm 16 oz. 

C. Potassium bichromate 20 ¢ 154 gr. 
Sulphuric acid 50 ccm 384 min. 
Salt 100 g 768 gr. 
Water 1000 ccm 16 oz. 


After bleaching in one of the baths, the prints should be 
washed for 20 to 30 minutes, and redeveloped in the fol- 
lowing : 


I. Metol 10¢ 7/ee: 
Sodium sulphite, dry 33 g 250 er. 
Sodium carbonate, dry 33 g 250 er. 
Water 1000 ccm 16 oz. 

II. Hydrochinon 33 g 250 gr. 
Potassium metabisulphite 16g 123 gr. 


Water 1000 ccm 16 oz. 


TONING BROMIDE PRINTS 230 


III. Ammonium carbonate 100 g 768 gr. 
Water 1000 ccm 16 oz. 

The tones are somewhat dependent on the make of paper, 
but the following will give a general idea of the tones obtain- 
able. Bleach in A; develop in equal parts of II and III, 
diluted with more or less water; rich purplish-brown tones 
are obtained. Bleach in equal parts A, B, C; develop in I; 
result, good blacks slightly wanting in depth. Bleach in B; 
develop in I; splendid velvety blue-blacks in the shadows, 
like carbon paper. Bleach in C; develop in 4 parts II, 6 
parts III and 2 parts water; distinct intense brown with pure 
whites. Bleach in C; develop in 1 part II, 1 part III, 1 part 
water; a good sepia, like sulphur toning. Bleach in C; 
develop in 2 parts II, 1 part III and 2 parts water; result, a 
bright brown. 


Sulphide Toning 


There are two principal methods of obtaining warm brown 
or sepia to purplish brown tones: the direct and the indirect. 
In the former, the image is converted into silver sulphide 
direct, while in the latter process the silver is first converted 
into chloride, bromide or iodide, and then into sulphide. 

Direct ProcessEs.—Alum and hypo (Baekeland).— 


Hypo 200 g 3 1/5 oz. 
Potash alum 46g 354 gr. 
Water 1000 ccm 16 oz. 


Dissolve the hypo, keeping the temperature of the solution 
near the boiling point, add the alum gradually with constant 
stirring, and allow to cool. Heat up to 50° to 60° C. (122° 
to 140° F.) each day for three days, and then add: 
Silver nitrate, 10% sol. 5to7ccm 40to 55 min. 
The bath must not be filtered. ; 
Alum-sugar-hypo (Baekeland ).— 


Hypo 202 192 gr. 
White sugar 40 ¢ 307 gr. 
Alum 25g 192 gr. 
Hot water 1000 ccm 16 oz. 


Mix as above. It is advisable to wash the prints thoroughly 
after fixing, and with some papers it is advisable also to 
immerse for 5 minutes in an alum bath, then briefly wash and 
tone. The bath should never be above 44° C. (110° F.), the 
best results being obtained at about 32° C. (90° F.), though 
toning at this temperature takes 30 minutes. 

Alum and hypo (Artura).—Specially recommended for 
development (gaslight) papers, but equally suitable for 
bromide prints: 


234 


SULPHIDE TONING 250 


A. Hypo 125 ¢ DOz: 
Potash alum 31g YZ oz. 
Hot water 1000 ccm 16 oz. 

B. Silver nitrate, 10% sol. 10 ccm 77 min. 
Salt, 10% sol. 10 ccm 77 min. 


As soon as A has cooled down, add B with constant stirring. 
The best temperature is 31° C. (88° F.), and toning takes 
from 15 to 30 minutes. 

Alum-gold-hypo (Artura) — 


Hypo 62.5 g 1 oz. 
Potash alum Bohai, Y4 oz. 
Sodium phosphate L5c:¢ V4 072. 
Hot water 1000 ccm 16 oz. 


Dissolve the salts in the order given. Add, when the solution 
is cold: 


Silver nitrate, 10% sol. 10 ccm 77 min. 

Potassium bromide, 10% sol. 10 ccm 77 min. 
Finally, add: 

Gold chloride, 1% sol. 13 ccm 100 min. 
The working temperature should be 35° to 39° C. (95° to 
We cere), 


When hot toning baths are used, the prints should be 


allowed to cool before washing; otherwise blisters are very .. 


likely to form. 
Colloidal sulphur (Lumiere ).— 


Hypo 125g ite: 
Hot water 1000 ccm 16 oz. 
Dissolve, and add: 
Yellow dextrine, 50% sol. 250ccm 4 oz. 
And, shortly before use, add: 
- Hydrochloric acid, pure 50 ccm 384 min. 


The bath will not keep more than about 2 hours. Prints 
should be immersed in the bath at a temperature of 18° to 


236 PHOTOGRAPHIC FACTS AND FORMULAS 


20° C. (65° to 68° F.) for 20 to 35 minutes, and apparently 
no change takes place; but, if washed for 114 hours, the sepia 
tone makes its appearance. 

Liver of sulphur or polysulphide process (Woodman) .— 
Wash the prints free from hypo, harden by immersion in 
formaldehyde solution, and place at once in a solution of 
liver of sulphur (sulphurated potash) made by dissolving 
a piece about the size of a pea in 200 ccm (7 oz.) water. 

Ammoniacal liver of sulphur (Vero)—The prints must be 
free from hypo and must not have been dried. Harden by 
10 minutes’ immersion in a 10 per cent solution of formalde- 
hyde, wash, and immerse in: 


Liver of sulphur 7g 54 gr. 
Water 1000 ccm 16 oz. 
Ammonia a few drops 


Toning is very rapid and purplish-brown tones are obtained. 
Ammonium sulphide (Kropf ).— 


A. Ammonium sulphide 25 ccm 192 min. 
Water 1000 ccm 16 oz. 
B. Ammonium carbonate 3.75 g 29 gr. 
Water 125 ccm BO: 
C. Ammonium persulphate 125 10 gr. 
Water 125 ccm 2 oz. 


Mix in the above order. The colour of the mixture should 
be greenish-yellow, and, in about half an hour, turn to 
golden yellow, when it is ready for use. Prints should be 
washed for a short time after fixing, and then immersed in 
the bath at normal temperature; toning takes about 15 min- 
utes. If heated to 30° C. (86° F.), toning is complete in 10 
minutes. 
Sodium sulphide-ferricyanide (Brown).— 
Sodium sulphide, 20% sol. 400 ccm 8 oz. 


SULPHIDE TONING 20% 


Potassium ferricyanide, 
20% sol. 200 ccm 4 oz. 
The mixture turns milky, but clears up on stirring well. 
Then add: 


Potassium bromide, 10% sol. 200 ccm 4 oz. 
Glacial acetic acid 50 ccm Y, 072. 


Stir until the precipitate dissolves. The prints should be 
well washed, and, in from 10 to 15 minutes after immersion 
in the bath, assume a very pleasing brown tone. 

Sulphide-ferricyanide (Blake-Smith).—Three stock solu- 
tions are required: 


A. Sodium sulphide, pure 100 g 4 oz. 
Water 400 ccm 16 oz. 
B. Sulphuric acid, pure 25 ccm 1 oz. 
Water 250 ccm 10 oz. 
C. Potassium ferricyanide 50 g 1 oz. 
Water 500 ccm. 10 oz. 
For use mix: 
A solution 60 ccm 460 min. 
Water 1000 ccm 16 oz. 
Then add: 
B solution 180 ccm 2 oz., 6 dr. 
And, finally, add: 
C solution 500 ccm 8 02. 


Toning should be complete in from 2 to 5 minutes. 
Ammonium sulphide-ferricyanide.— 


A. Potassium bromide llg 85 gr. 
Potassium ferricyanide oe 269 gr. 
Water 1000 ccm 16 oz. 

To this, add: 

B. Ammonium sulphide 25 ccm 192 min. 

Water 100 ccm 1Y4 oz. 


This last solution should be mixed just before use. 


238 PHOTOGRAPHIC FACTS AND FORMULAS 


Thiocarbamide-sulphide (Triepel) — 


Potassium bromide 10g /iget 
Potassium ferricyanide I5¢g 115 gr. 
Sodium sulphide 4¢ 31 gr. 
Thiocarbamide 2¢g 15.5 gr. 
Caustic soda 2g 15.5 gr. 
Water 1000 ccm 16 oz. 


INDIRECT ProcessEs.—The bleaching bath may be made 
either with a bromide, chloride or iodide. The correct 
formula for the bromide is: 


Ammonium bromide llg 85 gr. 
For the chloride 

Salt 6.6 g 50 gr. 
For the iodide: 

Potassium iodide 18.6 g 143 gr. 
Each should be added to: 

Potassium ferricyanide 35 g 269 gr. 

Water 1000 ccm 16 oz. 


If the halide salts be used in the above quantities, there is no 
loss in the intensity of the images, which will be the case if 
they are used stronger. The above may be kept as stock 
solutions. The following gives a somewhat colder sepia than 
the above: 


Potassium ferricyanide 6g 46 er. 
Ammonia 15 ccm 115 min. 
Water 1000 ccm 16 oz. 
Various modifications have been suggested, as: 
Potassium ferricyanide 232 177 gr. 
Potassium iodide l4¢g 107 gr. 
Ammonium persulphate l4¢g 107 gr. 
Water 1000 ccm 16 oz. 


Or: , 
Potassium iodide 23g 177 gr. 


SULPHIDE TONING eae 


Iodine 10 ¢g 77 gr. 
Water 1000 ccm 16 oz. 
In these last two baths the paper turns a deep blue, which 
may be discharged by immersion in a 2 per cent solution of 
potassium metabisulphite or sodium sulphite acidulated with 
a little sulphuric acid. 
The following was recommended (Greenall) for commer- 
cial work, as it saves the cost of the halides: 


Potassium ferricyanide 23 g 177 gr. 
Sodium phosphate ll5¢ 883 gr. 
Water 1000 ccm 16 oz. 


Bichromate baths have been recommended, but they require 
much longer washing to remove the yellow bichromate stain 
than the other baths. Sedlaczek’s formula is: 

Potassium bichromate, 


sat. sol. 100 ccm 1 oz. 
Hydrochloric acid, 10% sol. 100 ccm oye 
Potassium bromide 100 g 1 oz. 
Water 1000 ccm 10 oz. 

Blake-Smith recommended : 

Potassium bichromate 21g 160 gr. 
Sulphuric acid 40 ccm 307 min. 
Salt 100 g 768 gr. 
Water 1000 ccm 16 oz. 


Too long washing of the bleached prints causes yellow tones ; 
about 10 minutes in running water is enough. The toning 
solution is sodium sulphide, and the best results are obtained 
with the hydrated salt (pure analytical agent). Ordinary 
technical sulphide should be made into a stock solution and 
boiled for a short time until a black precipitate forms, or 
allowed to stand for several days, and then filtered. Old 
deliquesced salt should not be used, as it consists in great part 
of hypo and caustic soda, which reduce the strength of the 


240 PHOTOGRAPHIC FACTS AND FORMULAS 


print and cause blisters. A stock solution that will keep 
(Blake-Smith) can be made as follows: 


Sodium sulphide 330 g 5 OZ. 
Sodium sulphite, dry 5S0to65gr. %toloz. 
Water 1000 ccm 15 oz. 


For use dilute with 9 volumes of water. The bath should 
not be used too long. 
Ammonium or barium sulphide may be used instead of 
the sodium compound: 
Ammonium sulphide 10to20ccm 77 to 154 min. 


Water 1000 ccm 16 oz. 
Or: 

Barium sulphide 3.3 g 25 gr. 

Water 1000 ccm 16 oz. 


Shake the latter solution for a few minutes and allow to 
stand for any precipitate to settle, and then filter. The 
barium salt is more stable than the sodium and therefore 
preferable in practice. 

For chlorising or bromising the image, quinone has been 
recommended (Lumiére & Seyewetz) : 


Quinone 5g 3834 gr. 
Sodium chloride (salt) 6g 46 gr. 
Sulphuric acid 3.ccm 23 min. 
Water 1000 ccm 16 oz. 


Potassium bromide 11 g (85 gr.) may be used instead of the 
sodium chloride. The bleached images are amenable to 
exactly the same treatment as all other bleached images. 

Molybdenum and tin sulphur compounds, called sulpho- or 
thiomolybdates and stannates have been proposed (Smith) ; 
the former was introduced commercially as “Cubrome” and 
gives excellent results. This solution can be made as fol- 
lows: 

Ammonium molybdate 100 g 770 gr. 


SULPHIDE TONING 241 


Hot water 1000 ccm 16 oz. 
When cold, add in small quantities with constant stirring, 
ammonium sulphide sufficient to form a deep orange solu- 
tion. For use mix: 


Stock solution 100 ccm 7/0 min. 
Ammonia 10 ccm 77 min. 
Water 1000 ccm 16 02: 


If the whites of the prints are stained yellow, immerse for a 
short time in a 3 per cent solution of ammonia, and wash 
thoroughly. This gives excellent results with the bichromate 
bleaches. 

Sodium sulphostannate may be prepared as follows: 


Sodium sulphide, pure 30 ¢ 230 er. 
Water 1000 ccm 16 oz. 
Stannic sulphide 70g 538 gr. 


Dissolve the sodium salt in about one-fourth of the water, 
add the tin salt, and heat gently with constant stirring until 
dissolved; then dilute to bulk. Stannic sulphide is known 
also as tin disulphide, or bisulphide, or mosaic gold. One 
part of the above solution should be diluted with 9 parts of 
water for use. 

Sulphides plus developer—This method gives somewhat 
darker tones, as some black metallic silver is probably formed 
with the sulphide. The prints should be bleached as usual 
(Greenall), and then treated with the following: 


Metol lg FETE RW 
Potassium carbonate ieee 100 gr. 
Sodium sulphide, 1% sol. 3to5ccm 23 to 40 min. 
Water 1000 ccm 16 oz. 


This gives a warm black, which varies with increase of the 
sulphide. 

Valenta’s method requires three stock solutions: 
A. Pyrocatechin 20 g 154 gr. 


242 PHOTOGRAPHIC FACTS AND FORMULAS 


Sodium sulphite, dry 50 g 384 gr. 
Water 1000 ccm 16 oz. 
B. Sodium carbonate, cryst. 200 g SE VOZ, 
Water 1000 ccm 16 oz. 
C. Schlippe’s salt 10 ¢ 77 gr. 
Water 1000 ccm 16 oz. 


For use mix 2 parts A with 1 part B, and for sepia tones add 
2 per cent C; for warm brown tones add 4 percent C. 

Toning with mercury sulphides.—In this method the varia- 
tion of colour depends on the addition of more or less mer- 
cury salt to the image (Bennett). Two stock solutions are 
required for the bleaching bath: 


A. Ammonium bromide llg 85 gr. 
Potassium ferricyanide 35 g 269 gr. 
Water 1000 ccm 16 oz. 

B. Mercuric chloride 28 g 215 er. 
Potassium bromide 28 g 215 or 
Hot water 1000 ccm 16 oz. 

And two stock solutions for the toning bath: 

I. Sodium sulphide 330 g 5173-02: 
Sodium sulphite, dry 50 to 65 g 385 to 500 gr. 
Water 1000 ccm 16 oz. 

II. Schlippe’s salt 10g 77 gr. 
Water 1000 ccm 16 oz. 


The following table gives the colours obtainable with the 
various baths: 


Bleacher Toning bath 
_ Black A; ly Bal I 
Brown black Av 2 ;Bet I 
Deep brown A; Ss BRe I 
Dark brown A; 5 toi7 see I 
Deep warm brown A I 
Reddish brown A Titi 


SULPHIDE TONING 243 


Red brown A I,1;1I,4 
Very warm brown A bas Er 
Red chalk A i] 


Schlippe’s salt is also known as sodium sulphantimoniate. 
The crystals should be rinsed with water before use, and a 
drop or two of ammonia added to the stock solution. 

Various tones may also be obtained with mercury salts by 
the following baths. Bleach the prints in: 


Mercuric chloride I2¢ 02 gr. 
Potassium bromide I2¢ 92 er. 
Water 1000 ccm 16 oz. 


Wash thoroughly, and use the following baths for the various 


colours: 
Greyish-black : 


Hypo 10.5 g 80 gr. 

Water 1000 ccm 16 oz. 
Grey-violet: 

Hypo 10.5 g 80 gr. 

Potassium metabisulphite Sia 40 er. 

Water 1000 ccm 16 oz. 
Brown to violet-black : 

Hypo 18.75 g 144 gr. 

Cupric sulphate 18.75 ¢g 144 gr. 

Water 1000 ccm 16 oz. 


The addition of a few grains of sodium carbonate gives 
darker tones. 
Brownish-violet : 


Hypo 12.5¢ 96 gr. . 
Silver nitrate 42¢ 32 gr. 
Sodium metabisulphite 6.25 g 48 er. 
Water 1000 ccm 16 oz. 


It should be noted that all mercury toning gives intensifica- 
tion. 


244 PHOTOGRAPHIC FACTS AND FORMULAS 


Sulphide and Schlippe’s salt—vVariation of colour may be 
obtained by combining sodium or ammonium sulphide with 
Schlippe’s salt (Bishop). Ten per cent solutions of sodium 
sulphide and Schlippe’s salt should be made, or the com- 
mercial solution of ammonium sulphide may be used. For 
red-brown tones mix: 


Sulphide solution 25 ccm 192 min. 

Schlippe’s salt solution 75 ccm 576 min. 

Water 1000 ccm 16 oz. 
For warm brown: 

Sulphide solution 50 ccm 384 min. 

Schlippe’s salt solution 50 ccm 384 min. 

Water 1000 ccm 16 oz. 
For brown tones: 

Sulphide solution 75 ccm 576 min. 

Schlippe’s salt solution 25 ccm 192 min. 

Water 1000 ccm 16 oz. 


Carmine or red chalk tones —These can be easily procured 
by treatment of a sulphide toned print with gold sulpho- 


cyanide: 
Gold chloride 2.3 g 15 gr. 
Ammonium sulphocyanide 23g 150 gr. 
Water 1000 ccm 16 oz. 
The following (Blake-Smith) acts better: 
A. Gold chloride lg 15 gr. 
Water 225 ccm 7 Oz. 
B. Thiocarbamide 325 23 er: 
Water 1000 ccm 16 oz. 
C. Sulphuric acid 10 ccm 77 min. 
Water 1000 ccm 16 oz. 


_ For use mix 1 part each of A, B and C with 10 parts water. 
Allow the action to continue until the deepest shadows are 
toned. 


SULPHIDES TONING 245 


Reducing sulphide-toned prints—Sulphide toned prints 
may be reduced by treatment with most of the usual negative 
reducers or with chlorine and bromine water, solutions of 
iodide, permanganate, and sulphuric acid. The most satis- 
factory are solutions of cupric chloride or bromide, the 
latter for preference (Smith). The chloride reducer is 
equal parts of a 5 per cent solution of cupric chloride and a 
15 per cent solution of common salt. The bromide reducer is: 


Cupric bromide (Eafe 58 ger. 
Sodium bromide 62.5 g 480 gr. 
Water 1000 ccm 16 oz. 


The cupric bromide in this bath may be replaced by using 
8.5¢ (65 gr.) cupric sulphate, and increasing the sodium 
bromide by 8g (61 gr.). After reduction the prints should 
be immersed for 2 minutes in a 5 per cent solution of hydro- 
chloric acid, and washed for about 10 minutes. 

Partial development and sulphiding—bBleach the prints in 
the usual ferricyanide and bromide mixture, wash for 90 
seconds in running water, and immerse for various times in 
the following developer ; rinse for 30 seconds, and treat with 
the usual sulphide bath. 


Metol 18¢ 14 er. 
Hydrochinon 46¢ apa 
Sodium sulphite, dry 92¢ 70 gr. 
Borax 18.4 g 140 gr. 
Water 1000 ccm 16 oz. 


The following table shows the various tones obtained: 


246 PHOTOGRAPHIC FACTS AND FORMULAS 


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SULPHIDE TONING | 247 


GENERAL NoTEsS ON SULPHUR Tontnc.—R. Bullock of 
the Kodak Research Laboratory, finds that the character of 
the emulsion has considerable influence on the resulting 
colour; the faster the emulsion the more purple the colour, 
while slow papers tend to give yellowish tones. Also, with a 
given paper, the degree of development exerts some action, 
although this may be masked by the character of the emulsion. 
With a given paper and method of making the black and 
white print, the hypo-alum and liver of sulphur (potassa 
sulphurata) toning processes give practically identical results, 
while the indirect methods, that is, those in which the, image 
is bleached first, tend to give yellowish prints. The effect of 
a preliminary treatment of the black and white print with 
sulphide, prior to bleaching, is to give mixed direct and 
indirect sulphide toning; the results depending on the exact 
procedure followed, and, therefore, varying in colour. In 
the indirect process there is no advantage in increasing the 
ratio of the bromide to more than one-third of the ferri- 
cyanide. With 10 per cent of ferricyanide, the colour is more 
yellowish and the bleaching very rapid; with from 3 to 1 per 
cent, the bleaching is practically no longer and the colours 
normal: with much less than 1 per cent, bleaching is much 
~ slower but the colour just as good. The most advisable 
strength would thus appear to be 3 per cent, or 30g ferri- 
cyanide per liter (230 gr. to 160z.) with 10g (77 gr.) am- 
monium bromide respectively. No advantage is to be found 
by the use of chlorides, while with iodides the tones are more 
yellowish. For the sulphide bath, a strength of 3 per cent 
is the best, and the bath should be unsparingly used so as not 
to exhaust it. Dipping the prints for about 10 seconds into 
a 1 per cent solution of sodium carbonate, immediately before 
the sulphide bath, tends to give more purplish tones, particu- 
larly with development papers, and when a chloride bleach is 


248 PHOTOGRAPHIC FACTS AND FORMULAS 


used. The final conclusions are that: excessive bromide in 
the bleach leads to loss of image; too long washing after 
bleaching should be avoided, as well as weakness or too long 
use of the sulphide bath, and presence of hypo in the latter. 


The Carbon Process 


MAKING THE TissuE.—The gelatine mass is prepared with 
hard and soft gelatine in the ratio of 3:1, or the finest pale 
carpenter’s glue may be used, with an admixture of sugar 
candy; in very hot dry climates a little glycerine. The latter 
addition is not advisable under ordinary circumstances. A 
typical formula is: 


Gelatine 200 g 314 oz. 
Sugar candy 50 g 384 gr. 
Water 1000 ccm 16 oz. 
Colouring pigment 4tol0g 30to/77 gr. 


Soak the gelatine and candy in the water for about 30 minutes 
and melt on a water bath. The pigment should be the finest 
powder colours, as used by artists. It should be worked up 
with a muller on a sheet of glass with a little of the gelatine 
solution, and added to the remainder of the solution, well 
stirred and strained through linen. 

Tue Cotours.—The colours can be mixed in various pro- 
portions, so that any shade may be obtained, and these should 
be judged by their appearance when mixed with a little of the 
gelatine solution and dried. 

Chocolate brown.—Indian ink 6, English red 4, alizarin 1, 
dissolved in a little soda solution, purpurine 1 part. 

Engraving black—Lamp black 19, carmine lake 10, indigo 
10 parts. 

Warm black.—Lamp black 6, carmine lake 6, burnt umber 
4, indigo 2 parts. 

Dark brown.—Indigo 2¥, Indian red 6, carmine 1144, Van- 
dyke brown 4, lamp black 30 parts. 


249 


250 PHOTOGRAPHIC FACTS AND FORMULAS 


Red brown.—lIndian ink 6, carmine 8, Vandyke brown 8 
parts. 

Sepia.—Lamp black 4, sepia 35 parts. 

Pure black.—lIndian ink 15, Vandyke brown 2, Venetian 
red 2 parts. 

Violet black—Indian ink 20, indigo 2, carmine 1 part. 

Red chalk.—English red 10, Italian red 5, lamp black 0.03 
parts. ) 

Transparency tissue for enlarged negatives, and positives. 
—Indian ink 2, Indian red 3, carmine lake 5 parts. 

To Coat sy Hanp.—Strain the warm mixture into a flat 
dish standing in warm water, and clear the bubbles off the 
surface with a strip of paper or thin card. Hold the paper 
to be coated upright at the further end of the dish, its lower 
edge just touching the liquid, and gently lower it on to the 
surface. Float for 2 minutes, and raise with a steady mo- 
tion; allow to drip and hang up to dry. 

SENSITISING.—Either ammonium or potassium bichromate 
may be used: 

Potassium bichromate 21 to 63g 160 to 480 gr. 

Water 1000 ccm 16 oz. 

Ammonia q.s. q.s. 
Enough ammonia should be used to make the solution smell 
distinctly. For weak negatives use the weakest bath, for 
normal negatives the mean, and for harsh negatives the 
strongest bath. Immerse the tissue for 3 minutes, and dry in 
the dark. The temperature of the solution should be 15° C. 
COOcaE ) 

The following gives a tissue that will keep better: 
Potassium bichromate 20 g 240 er. 
Citric acid 5g 60 gr. 
Ammonia eh dink 


—_-- 


THE CARBON PROCESS 251° 


Water 1000 ccm 25 oz. 
Use as above. 

QUICK-DRYING SENSITISER.—This is convenient, as the 
tissue will readily dry in from 15 to 30 minutes. 2 § 
Ammonium bichromate 60 g 460 er. 
Water 1000 ccm 16 oz. 
Immediately before use mix 2 parts of the above with 3 
parts of alcohol or acetone. The tissue may be immersed in 
this for 3 to 4 minutes, or the solution may be painted on 

freely. The alcoholic mixture will not keep. 
SINGLE TRANSFER PApEerR.—Brush over plain paper: 

Soft gelatine 60 g 460 er. 
Water 875 ccm 14 oz. 
Soak the gelatine for 30 minutes, dissolve in a water bath, 
and raise nearly to the boiling point; add with constant 

stirring : 
Chrome alum {25/2 10 gr. 
Water 125 ccm 2 oz. 
The mixture must be rapidly used and kept hot, or it will 
gelatinise. The following may be easily applied with a broad 
flat brush and dries rapidly: 


Soft gelatine 72g 54 gr. 
Glacial acetic acid 35 ccm 270 min. 
Water 275 ccm 4YZ oz. 


Soak the gelatine in the acid and water for 30 minutes, and 
dissolve by heat; add slowly with constant stirring: 


Alcohol 680 ccm 11¥4 oz. 
Then add in the same way: 

Chrome alum l6¢g 12% gr. 

Water 14 ccm 110 min. 


This solution will keep. 
FLEXIBLE TEMPORARY Support.—Gelatinised paper is 
coated with a resinous solution. As a rule, a baryta-coated 


252 PHOTOGRAPHIC FACTS AND FORMULAS 


paper is used, either matt or glossy, which may be prepared as 
follows: 


Gelatine 100 g 134 oz. 
Barium sulphate 30 g 250 or. 
Glycerine 5 ccm 38 min. 
Water 940 ccm 14 oz. 


Soak the gelatine in water, dissolve by heat, and add the 
baryta rubbed into a cream with the glycerine. Add very 
carefully, almost drop by drop, with constant stirring: 
Chrome alum 16g 13 gr. 
Water 60 ccm 202 
Paint the mixture thickly over the paper, or else float it 
twice, hanging up by opposite ends each time. Obviously, 
single transfer or commercial baryta paper may be used. 
WaxInGc SoL_utTion.—The temporary support has to be 
waxed prior to use, and the following may be used: 


Beeswax | 20 g 154 gr. 
Powdered resin 20 g 154 ger. 
Turpentine 1000 ccm 16 oz. 


Melt the wax in a water bath, add the resin, and stir until 
dissolved; then add the turpentine gradually with constant 
stirring. This takes from 12 to 24 hours to dry; if ether be 
substituted for the turpentine, it will dry in a few minutes. 
Caution.—The water in the bath should boil, and then the 
gas be turned out, as the vapours of both turpentine and ether 
are explosive. This should be applied to the paper with a 
pad, polished off with a dry pad, and then hung up to dry. 
ALUM BATH FoR DISCHARGING BICHROMATE STAIN.— 
Alum 62.5 g loz 
Water 1000 ccm 16 oz. 
CoOLLODION FOR DouUBLE TRANSFER FROM OpAL.—This 
gives an extremely fine matt surface, without any glaze, if 


WHE CARBON “PROCESS 253 


matt surface glass be used; if polished opal be used, a high 
gloss is obtained: 


Pyroxyline 8.5 g 65 gr. 
Alcohol 500 ccm 8 oz. 
Ether 500 ccm 8 oz. 


Opa Giass, Ivory or Woop Aas FINAL SuPPORT.—Coat 
with the chrome gelatine mixture given above under single 
transfer paper. For canvas, the surface paint should be 
removed by scrubbing with hot soda solution, about 10 per 
cent, until nothing but the priming is left. Paint freely with 
the chrome-gelatine mixture, dry thoroughly, rub down 
smooth with fine sandpaper, and repeat the operations about 
four times. The print should be finally soaked in the gelatine 
solution, and squeegeed into contact. 

SUBSTRATUM FOR TRANSPARENCIES.—Either of the fol- 
lowing may be used: 


Gelatine 40 g 307 gr. 
Water 1000 ccm 16 oz. 
Potassium bichromate 4¢ Stigr: 


Coat the glass thinly, dry, and expose to light for 30 minutes ; 
then wash and dry. Or the glass may be coated with the 
following, which keeps well: 


Gelatine 7g 54 gr. 

Glacial acetic acid 34 ccm 260 min. 

Water 270 ccm 414 oz. 
Dissolve by heat, and add slowly: 

Alcohol 680 ccm 11 oz. 

Phenol (carbolic acid) 10 ccm 77 min. 
Then add, with constant stirring: 

Chrome alum 0.75 g 534 er. 

Water 14 ccm 107 min. 


To INTENSIFY CARBON TRANSPARENCIES.—Immerse in: 


254 PHOTOGRAPHIC FACTS AND FORMULAS 


Potassium permanganate 5¢g 38 gr. 
Water 1000 ccm 16 oz. 
Rinse and dry. Weak solutions of acid aniline dyes may also 
be used, about 0.5 per cent. By the use of the latter it is 

possible to alter the colour in any desired manner. 


The Gum-Bichromate Process 


PIGMENTS FOR GuM-BicHRoMATE (Kosel)—Powder or 
tempera colours should be used. 

Warm brown: Bone black, 5 parts; Vandyke brown, 3 
parts; ivory black, 2 parts; Indian red, 1 part. 

Purple brown: Ivory black, 5 parts; Vandyke brown, 4 
parts; dark alizarin lake, 2 parts; Indian red, 1 part. 

Yellowish brown: Ivory black, 5 parts; bone black, 5 
parts; burnt sienna, | part. 

Dark brown: Bone or ivory black alone. 

Brown (for sunset effects): Bistre. 

Brown, medium shade: Bone black, 5 parts; Vandyke 
brown, 4 parts; burnt sienna, 1 part; Indian red, 1 part. 

Bright brown: Bone black, 5 parts; Vandyke brown, 4 
parts; sienna, 4 parts. 

Deep brown: Ivory black, 5 parts; Vandyke brown, 3 
parts; Indian red, 1 part. 

Blue: Ivory or peach black, 5 parts; indigo, 5 parts; 
Paris blue, 1 part. 

Dark green: Bone black, 5 parts; Paris blue, 2 parts. 
Or: Bone black, 5 parts; indigo, 5 parts; blue black, 5 
parts; Paris blue, 1 part ; cadmium yellow, 1 part. 

Bright green: Vandyke brown, 3 parts, Paris blue, 1 part. 

Olive green: Sienna, 2 parts; indigo, 2 parts; bone black, 
5 parts. 

Red: Ivory black, 5 parts; burnt sienna, 2 parts; Indian 
red, 2 parts. 

Warm red: Bone black, 5 parts; red chalk, 3 parts; 
Indian red, 1 part. 


250 


256 PHOTOGRAPHIC FACTS AND FORMULAS 


Dark red: Peach black, 2 parts; alizarin lake, 1 part; 
Indian red, 1 part. 

Black, for pencil drawings: Graphite. 

Black: Peach or blue black. 

Warm black: Ivory black. 

ARABIN GuUM-BICHROMATE ProceEss.—The best Soudan 
gum arabic should be sifted through a 40 mesh sieve. Take: 


Hydrochloric acid 7.5 COM 127 min. 
Water 150 ccm 514 oz. 


Heat to 50° C. (122° F.), sift in 100 g (3% oz.) of the gum, 
and stir until dissolved; then add methyl alcohol, 600 ccm 
(210z.), and stir until the arabin is precipitated. Filter 
through linen, and squeeze out as much alcohol as possible. 
Then break up the lump, put in jar, and cover with fresh 
alcohol; leave for some hours with constant stirring until 
all the water has been absorbed by the alcohol. Squeeze dry, 
spread out to thoroughly dry, and powder. To make the 
coating mixture, take: 


Arabin 20 g 300 er. 
Magnesium carbonate 20 g 300 er. 
Water 40 to75ccm 1% to 2% oz. 


The quantity of water depends on the thickness of the solu- 
tion desired. Mix the pigment of the desired colour with the 
above until a thick cream is formed, add an equal volume of 
15 per cent solution of ammonium bichromate, and spread 
on paper. Development is effected in the usual way with 
water at about 35° © (95> Bi); 

FORMULA FoR PurE WHITES.—Frequently pure whites are 
difficult to obtain with this process, and the following is said 
to obviate this trouble: 


Potassium bichromate /2¢ 550 gr. 
Water 450 ccm 7% 02. 


Dissolve by heat, add enough ammonia to make the solution 


THE GUM-BICHROMATE PROCESS Zoh 


smell distinctly, and then heat to drive off excess of ammonia. 
Beat the whites of several eggs to a froth, and allow to 
stand for 24 hours to liquefy. The pigmenting solution is: 


Bichromate sol., above 450 ccm 7 02. 
Cupric sulphate 90 g 720 er. 
Gum arabic, powdered 800 ¢ 13% oz. 
Pigment 600 g 10 oz. 
Albumen 200 ccm Shy Mara: 
Glycerine 100 ccm 768 min. 


Mix well, and apply as usual to the paper. 


The Iron Processes 


FERROPRUSSIATE OR CYANOTYPE Process.—This process 
is much used for the preparation of engineering and 
draughtsman’s plans, giving white lines on a blue ground, 
that is to say, a blue image is formed by the action of light. 
The sensitive solutions can be made as follows: 


A. Ferricammonium citrate (red) 250 ¢ 4 oz. 
Water 1000 ccm 16 oz. 
Filter. 
B. Potassium ferricyanide 200 g 3. 1/S:027° 
Water 1000 ccm 16 oz. 


Filter. The ferricyanide must be in perfectly clear ruby-red 
crystals, free from any adherent yellow powder; it is advis- 
able to allow a little more in weighing out, and place the 
crystals in a flask; pour in some distilled water, shake, pour 
off the water, and repeat this operation; then add the water 
for the solution, and heat until dissolved. Mix the two solu- 
tions in equal volumes and filter. Either float the paper on 
the solution for 3 minutes, or paint the solution on freely 
with a broad flat brush, and dry as quickly as possible, prefer- 
ably by heat. A much more sensitive paper is obtained by 
using the green ammonio-citrate of iron; then the solutions 
should be: 
A. Ferric ammonium citrate 


(green) 125 ¢ 2 oz. 

Water 500 ccm 8 oz. 
Filter, and add: 

B. Potassium ferricyanide 45 ¢ 346 gr. 

Water 500 ccm 8 oz. 


258 


Ke 


THE TRON PROCESSES 259 


Filter. The method of using is as above. Brighter prints 
are obtained by the addition of 0.5 per cent of oxalic acid to 
the above; the paper keeps better if 0.05 per cent of potas- 
sium bichromate is added. 

The use of sodium or ammonium ferric oxalate gives 
greater speed than the above, but the paper does not keep so 
well. The sensitiser should then be: 


Potassium ferricyanide jem ie 1021 gr. 
Ferric ammonium citrate (red) 166 ¢ 1277 gr. 
Sodium or ammonium ferric 

oxalate | 33 ¢ Zo Et 
Water 1000 ccm 16 oz. 


All these solutions are sensitive to light. Other iron salts 
may also be used, for instance: 
A. Sodium or ammonium ferric 


oxalate 250 g 4 oz. 
Water 1000 ccm 16 oz. 

B. Potassium ferricyanide 250 g 4 oz. 
Water 1000 ccm 16 oz. 


Filter both solutions, mix, and again filter. Or the follow- 
ing may be used: 


A. Tartaric acid 180 g 1382 gr. 
Ferric chloride, anhydrous 68 g S22 et, 
Ammonia q. Ss. q. S. 
Water 1000 ccm 16 oz. 


Dissolve the acid in three-fourths of the water, then add the 
iron, and, when dissolved, add sufficient ammonia to neu- 
tralise the acid, about 175ccm (2%0z.) being required; 
excess of ammonia must be avoided. Filter, and add to: 

B. Potassium ferricyanide 217 ¢g 1666 gr. 
Water 1000 ccm 16 oz. 
Mix the two solutions. This gives greater sensitiveness, but 

the prepared papers to not keep so well as the others. 


260 PHOTOGRAPHIC FACTS AND FORMULAS 


It is important that the paper base should be free from 
wood pulp, preferably sized with starch, and with a hard 
surface. It has been suggested to add white dextrine to the 
sensitiser, but this lowers the keeping quality. The paper 
should be exposed preferably to sunlight until the ground, 
corresponding to the whites of the negative or plan, appears 
a dark olive-green; it should then be thoroughly washed with 
running water, and the lines should appear white on a deep 
blue background. With stale paper or with excess of or 
impure ferricyanide, the lines will appear more or less tinted. 
With underprinting the colour is more or less pale. Fre- 
quently, by somewhat prolonging the washing, the lines will 
clear up; or this can be much curtailed by using a 0.01 per 
cent solution of ammonia or sodium carbonate. This gives 
a violet tinge to the blue, and this can be corrected by subse- 
quent treatment with an acid, 5 per cent of hydrochloric, 
oxalic or sulphuric acid, or alum solution of the same 
strength. A much more stable and contrasty image is ob- 
tained if the print is developed with a 0.2 per cent solution 
of potassium ferricyanide, and well washed for four or five 
minutes. 

Numerous methods have been suggested for toning blue 
prints, but, as a rule, the results are extremely unsatisfactory. 
Immerse the dry print in: 

Ammonia (sp. gr. 897) 12.5 ccm 96 min. 

Water 1000 cem 16 oz. 
As soon as the blue color disappears, wash for a few minutes, 
and then immerse in a 2 per cent solution of tannin; this 
gives a blackish colour, but the outlines may become blurred 
from spreading of the colour into the whites. Or the print 
may be well washed in distilled water, and bleached in yellow 
light in: 

Silver nitrate 20 g 154 gr. 


pai TRON PROGRESSES 261 


Water 1000 ccm 16 oz. 
Wash with distilled water, and fume with ammonia, expose 
to light, and develop with ferrous oxalate; then wash thor- 
oughly. 

The cyanotype process may be used for making lantern 
slides or transparencies, though, naturally, the colour is suit- 
able for but few subjects. The sensitising solution is rather 
weaker than used for paper: 

A. Ferric ammonium citrate 


(green ) 250 g 4 oz. 
Water 1000 ccm 16 oz. 

B. Potassium ferricyanide 100 g 768 gr. 
Water 1000 ccm 16 oz. 


Mix in equal volumes and filter. Gelatinised glass (fixed out 
dry plates may be used) should be immersed for 5 minutes, 
and rapidly dried. The sensitiser will not keep when mixed. 
The plates should be exposed like the paper, and washed in 
the same way. 

PELLET’S oR GuM-IRON Process.—This process gives blue 
lines on a white ground, thus the reverse of the cyanotype 
process, from a drawing or plan. The paper has very poor 
keeping qualities. Originally patented by Pellet. Three 
stock solutions should be prepared (Pizzighelli) : 


A. Gum arabic 200 g 31/5 oz. 
Water 1000 ccm 16 oz. 

B. Ammonio-citrate of iron (red) 500 ¢ 8 oz. 

: Water 1000 ccm 16 oz. 
C. Ferric chloride 500 ¢ 8 oz. 
Water 1000 ccm 16 oz. 


These solutions will keep indefinitely in the dark, with the 
exception of A, which becomes acid in about a week. For 
use mix in the following order: 

A solution 200 parts 


262 PHOTOGRAPHIC FACTS AND FORMULAS 


B solution 80 parts 

C solution 50 parts 
It is important to adhere to this order, for, if A be added to 
C, the mixture becomes lumpy and useless. The mixture is 
at first thin and fluid, but soon becomes more viscous, and in 
a few hours cloudy and of the consistence of soft butter. It 
should be used in this condition and will keep in the dark for 
several days. Haugk recommended: 


Gum arabic solution, 1:5 300 to 350 parts 
Ammonium ferric oxalate solution, 6:10 100 parts 
Ferric chloride solution, 1:2 20 to 30 parts 


Float the paper on this mixture. Another excellent formula 
(Waterhouse) is: 


A. Gum arabic 170 g 6 oz. 
Water 650 ccm 22,02; 

B. Tartaric acid 40g 617 gr. 
Water 150 ccm ahere 

C. Ferric chloride solution, 

. sp. gr. 1.453 100 to 120g 1543 to 1851 gr. 


Filter the gum solution through a sponge or pad of cotton, 
and mix with the acid; then add the iron solution, which 
should be weighed, not measured, with constant stirring. 
Allow the mixture to stand in the dark for 24 hours, and add 
water to make the specific gravity 1.100. Well-sized paper, 
preferably gelatine-sized, should be fastened by pins to a 
flat board, and the mixture applied not too thickly with a flat 
brush. As soon as the brush begins to drag, the coating 
should be evened out with a round brush with circular strokes. 
This operation should be performed by artificial light, and 
the paper rapidly dried in the dark. The paper should be 
kept under pressure. The exposure will be from 15 to 40 
seconds in the sun, or proportionately longer in diffused 


THE TRON PROCESSES 263 


light under a drawing; the image is seen in a bright yellow 
colour on a darker ground. 

Development is effected with a 20 per cent solution of 
potassium ferrocyanide; the paper may be pinned to a 
board, and a very soft brush, charged with the solution, 
passed over the surface, care being taken not to rub up the 
image. Or the edges of the paper may be turned back to the 
height of about an inch and the print floated, face down, on 
the solution. The edges are turned up to prevent any solu- 
tion touching the back of the print, which would cause blue 
stains. In about half an hour, if the print is floated, a corner 
may be turned back and the image examined; if it is fully 
visible, the print should be washed with a spray or in run- 
ning water for a short time, immersed in a 1 per cent solu- 
tion of hydrochloric or sulphuric acid, the surface gently 
rubbed with a soft brush to remove the slight blue deposit, 
then again washed in water, again brushed, and hung up to 
dry. Corrections can be made with solution of potassium 
oxalate, about 15 per cent, thickened if necessary with gum 
arabic. 

FERROGALLIC OR INK Process.—This is also sometimes 
known as Colas’s process. It gives black lines on a white 
ground. The sensitiser is a mixture of ferric chloride or 
sulphate, and tartaric acid, thickened with gum, or gelatine: 


Ferric chloride 50 g 1 oz. 

Ferric sulphate, basic 22.8, 4 oz. 

Tartaric acid 45 ¢ 432 ger. 

Water 500 ccm 10 oz. 
Dissolve, and add: 

Gelatine Zoe V4 oz. 

Water 250 ccm 5 oz. 


Soak the gelatine in the water for 30 minutes and melt with 


264 PHOTOGRAPHIC FACTS AND FORMULAS 


heat. Filter the mixture through fine linen. Or the follow- 
ing may be used: 


Gum arabic 100 g 768 gr. 
Ferric chloride 328 g 2519 gr. 
Tartaric acid 220 g 1690 gr. 
Ferric sulphate, basic 220 g 1690 gr. 
Water 1000 ccm 16 oz. 


Dissolve in the above order and filter. The following (Fisch) 
is only suitable for heavily sized or gelatinised papers: 


Ferric chloride 100 g 768 gr. 
Water 500 ccm 8 oz. 
Dissolve, and add: 
Tartaric acid 30 g 230 gr. 
Water 500 ccm 8 oz. 
Or the following (Shawcross) may be used for any paper: 
Gelatine 137 g 1052 gr. 
Ferric sulphate, basic 55g 422 er. 
Sodium chloride 87 g 668 gr. 
Tartaric acid I7 g 130 gr. 
Ferric chloride 137 g 1052 gr. 
Water 1000 ccm 16 oz. 


The solutions should be applied with a broad flat brush or 
pad by artificial light, and rapidly dried. The paper will keep 
for 2 or 3 weeks. Exposure should be made under a drawing 
for about 10 minutes in sunlight, or until the lines appear 
yellow on a white ground. Development is effected on: 


Gallic acid 6g 46 gr. 

Oxalic acid lg 77 gr. 

Water 1000 ccm 16 oz. 
Or: 

Gallic acid 12.5 ¢ 96 gr. 

Alum 1255 96 gr. 


Water 1000 ccm 16 oz. 


tat ONG PROCESSES 265 


The image should become black in from 3 to 5 minutes. The 
print may be completely immersed in the developer or floated 
on its surface. As soon as the image is intense enough, wash 
with repeated changes of water, gently blot off the surface 
water, and hang up to dry in a warm place. It should be 
noted that the ferric sulphate used in this process is the basic 
variety, also known as subsulphate, or Monsell’s salt. 

GREASY OR PRINTER’S INK Process.—In this process the 
solubilisation of a colloid by the action of light on the iron 
salts, and the capacity of the insoluble colloids for taking 
greasy ink is employed; it was suggested by Fisch: 


Gum arabic 320 g 2451 gr. 

Water 1000 ccm 16 oz. 
Dissolve, and add: 

Wartaric acid 70g 540 er. 

Water 250 ccm 4 oz. 


And add, with constant stirring : 
Ferric chloride solution, 


45° Be. BZN Ors 023 200 Ef, 

Then add: 
Manganese sulphate 10g 77 oT. 
Water 25 ccm 192 min. 


Allow to stand in the dark for several hours, and then filter 
through fine muslin. Coat the paper in the usual way, and 
dty ato) to 45° C. (95° to 113° F.). Or the following 
may be used: 


Gum arabic O20.2 2496 gr. 

Water 1000 ccm 16 oz. 
Dissolve, and add: 

Tartaric acid 75 2 576 gr. 

or Citric acid 300 g 44/5 oz. 


Then add, with constant stirring: 
Ferric sulphate | 26g 200 er. 


266 PHOTOGRAPHIC FACTS AND FORMULAS 


or Ferric nitrate 400 g 64 oz. 
And add in the same way: 

Uranium nitrate 6g 46 gr. 

or Uranium chloride 200 g 31% oz. 


Finally, add: 
Ferric chloride solution, 
sp. gr. 1.453 210 ccm 3Y oz. 

Filter through muslin and coat well-sized paper therewith. 
The exposure will be from 3 to 6 minutes in sunlight. Place 
the print face up on a sheet of zinc or glass, and with a roller 
lightly charged with printer’s ink roll up the surface until 
uniformly grey. Immerse the inked print in cold water, 
transfer to a metal or glass plate supported at an angle, and 
allow a spray or stream of water to play over the surface; 
with a pad of absorbent cotton gently rub the print. The 
exposed parts will be gradually dissolved, leaving only the 
inked parts. 

TRUE-TO-SCALE Process.—A cheap and ready process for 
obtaining a few, about 25, pulls in printer’s ink from line 
drawings, etc. A good black original is the best. Ferro- 
prussiate or cyanotype paper should be exposed under the 
plan or drawing, and without development laid down on a 
“graph” or jelly, gently rubbed into contact, and immediately 
stripped. The jelly is now rolled over with a good letter- 
press ink with a composition roller and it only takes on the 
lines. A piece of paper is now laid on the jelly and rolled 
over lightly with a light roller, and, on lifting, the impression 
will be found on the paper. Inking must be done before each 
pull. The jelly can be made as follows: 


Glue 500 g 8 oz. 
Water to make 1000 ccm 16 oz. 
Allow to soak for some hours, melt with heat, and add: 
Gelatine 62.5 g 1 oz. 


a 


THE IRON PROCESSES 267 


Water to 125 ccm 2 oz. 
Soak, melt by heat, and add: | 
Ferrous sulphate 33.3 g 4 oz. 
Glycerine 33.3 ccm 4 02. 
Strain, and cast into flat tins. Or the following may be used: 
Gelatine 450 ¢ 1 Ib. 
Water 2550 ccm 90 oz. 
Size powder 450 g 1 Ib. 
Iron alum 42¢ 1Y4 oz. 
Water 570 ccm 20 oz. 


Dissolve the gelatine in the water; then add the size powder. 
Dissolve the alum in the water, and add to the gelatine-glue 
solution gradually, stirring all the time. Pour into tins or on 
a slab. After use it can be remelted and used again, but a 
little fresh jelly should always be added. Or the following 


(Albert) : 
Gelatine 160 g 1228 gr. 
Glycerine 15 ccm 115 min. 
Ox-gall 25 g 192 gr. 
Ferrous sulphate 2g 15.4 gr. 
Water to 1000 ccm 16 oz. 


Soak the gelatine in water, melt, add the other. ingredients, 
and, finally, the iron salt dissolved in a little water. Cast on 
zinc which has been roughened with emery to cause it to 
adhere well. The coating should be 2mm (1/25 in.) thick. 

PLAYERTYPE.—This is a method of copying printed matter 
invented by J. H. Player, in which a sheet of sensitive paper, 
bromide or development (gaslight), is placed face down on 
the printed matter, pressed into contact and exposed through 
the back. On development a negative copy is obtained. The 
slower papers are more suitable; the paper should be pressed 
into contact by a sheet of plate glass, and the latter covered 
with a yellow filter which can be made by immersing fixed out 


268 PHOTOGRAPHIC FACTS AND FORMULAS 


dry plates in a 2 per cent solution of tartrazin. The exposure 
varies from 30 seconds to 2 minutes, according to the sensi- 
tiveness of the paper and the strength of the light. The 
developer should be preferably hydrochinon well restrained 
with bromide, as generally used for line work. Printing-out 
paper may be used in the same way. And also the following 


(Albert) : 
Albumen 60 ccm 460 min. 
Fish glue, Le Page’s 40 ccm 307 min. 
Ammonium bichromate 45 ¢ 346 gr. 
Water 1000 ccm 16 oz. 
Or: 
Fish glue 37.5 ccm 288 min. 
Ammonium bichromate 3g Zo gn 
Grape sugar 3256 25 gr. 
Water 1000 ccm 16 oz. 


Dissolve the sugar in about one-fourth of the water before 
adding the other ingredients. Glass should be coated with a 
whirler and exposure is best effected with a half-watt lamp 
at a constant distance, the glass being placed with the coated 
side down on the drawing. Development is effected with hot 
water, and the print can then be stained up with a solution 
of a dye, such as chrysoidin, water soluble nigrosin, or by 
immersion in a 4 per cent solution of potassium permangan- 
ate, which gives a deep brown image of manganese dioxide. 

CopaALTt-IRon PriIntinG (Burian).—This process seems 
more suitable for line drawings than prints from ordinary 
photographic negatives. 


Oxalic acid 8g 61.5 gr. 

Water 30 ccm 230 min. 
Heat until dissolved, and add: 

Ammonium oxalate, neutral 24¢ 184 gr. 


When dissolved, add: 


Pr IkhON “PROCESSES 269 


Cobalt carbonate 8g 61.5 gr. 
Effervescence takes place, and the mixture should be digested 
until it turns red. The cobalt carbonate can be made by 
adding 39 g (299.5 gr.) crystallised sodium carbonate to 16 g 
(123 gr.) of crystallised cobalt chloride, and washing and 
drying the precipitate. To the above red liquid, cooled down 
Horaa ©. (95° F.), add: 

Lead peroxide 5¢g 38.5 gr. 

Glacial acetic acid 3 ccm 23 min. 

On shaking, the solution turns a deep green. From this point 
all further operations must be conducted by yellow light. 
Add: 

Lead peroxide 5g 38.5 gr. 
Glacial acetic acid 3 ccm 23 min. 
Pour the solution out into a flat dish, and allow to evaporate 
until crystals form and it is dry. Add 10ccm (77 min.) of 
water, filter, and make the bulk up to 1000ccm (160z.). 
The iron salt is obtained by mixing 20g (154 gr.) of ferric 
sulphate with ammonia, washing the precipitate, and adding 
36g (276.5 gr.) of acid ammonium oxalate. This can be 
made by adding 30ccm (230min.) of ammonia to 100g 
(768 gr.) of oxalic acid, gently heating, adding more am- 
monia until the solution smells distinctly of ammonia, then 
heating to drive off excess of ammonia, adding 100¢ 
(768 gr.) of oxalic acid, heating until dissolved, and allowing 
to crystallise. The actual sensitising solution is made by 
mixing 2 parts of the cobalt solution with 1 part of the iron. 
Paint on the paper with a brush and dry rapidly; the paper 
should be a green colour. Exposure may be to daylight or 
an arc, and the image should show a bright yellow on the 
green ground. Development is effected in a 1 per cent solu- 
tion of potassium ferricyanide until the whites appear white; 
then briefly wash and immerse in 1 per cent hydrochloric 


270 PHOTOGRAPHIC FACTS AND FORMULAS 


acid; again wash and immerse in a 1: 400 solution of sodium 
sulphide until the paper turns grey; then wash until white. 
The sensitised paper will only keep about 6 hours. If the 
ordinary ferric oxalate be used, the process is said to be 
suitable for ordinary negatives. 

KALLITYPE.—This is a silver-iron printing process, based 
on the light-sensitiveness of ferric salts, which are reduced 
to the ferrous state. The ferrous salts dissolve in the devel- 
oper, and reduce silver nitrate to the metallic state at the 
points where the ferric salt has been reduced by light. 

Hall’s Formulas.— 


A. Ferric oxalate 200 g 1 oz. 
Gum arabic 20 g 48 er. 
Water 1000 ccm 5Oz: 

B. Ferric potassium oxalate 62.5 g Y, oz. 
Water 1000 ccm 8 oz. 

C. Oxalic acid 125 g 4 oz. 
Ammonia 52 ccm 100 min. 
Water 1000 ccm 4 oz. 

D. Potassium bichromate 62.5 g 120 gr. 
Water 1000 ccm 4 oz. 


For use mix 480 parts A, 240 parts B, 30 parts C, and 4 parts 
D. Then add silver nitrate, dry, 37.5 parts. For thin and 
soft negatives, increase the proportion of D from 30 to 50 
per cent, and reduce the proportion of C by one-half or more. 


Developer : 
Sodium acetate _ 125¢ 1 oz. 
Tartaric acid Zoe 12 gr. 
Solution D, above 5to50ccm 10to 100 min. 
Water 1000 ccm 8 oz. 
Clearing bath: 
Sodium citrate 31.25 g ¥4 oz. 


Citric acid 5g 20 gr. 


THE IRON PROCESSES niet 


Water 1000 ccm 8 oz. 
Wash the prints well and fix in: 
Hypo 50 g 1 oz. 
Ammonia 12.5 ccm 120 min. 
Water 1000 ccm 20 oz. 
Thomson's formulas.— 
Ferric oxalate 150 g Hara a 
Ferric ammonio-citrate, brown 20g 10 gr. 
Cupric chloride 1&8 ¢ 9 gr. 
Gum arabic 20 g 10 gr. 
Water 1000 ccm 1 oz. 


Dissolve the ferric oxalate in warm water and allow to stand 
all night; then add the other ingredients, and filter. The 
solution will not be clear. Print until the deepest shadows 
are well visible. The developer is composed of equal parts 
of a 5.2 per cent solution of Rochelle salts and a 9.4 per cent 
solution of borax with the addition of 0.02 to 0.8 per cent 
potassium bichromate, which keeps the whites pure and acts 
as a restrainer. The prints should be left in the developer 
for 30 minutes, well rinsed, then fixed in: 


Hypo 31.25 g 240 gr. 
Ammonia 7.8ccm 60 min. 
Water 1000 ccm 16 oz. 


Wash for 30 minutes. 
Thomson's later formulas.— 


1. Ferric ammonio-citrate, brown 20¢ 10 gr. 
Ferric oxalate 66 g 33 gr. 
Potassium oxalate 74 ¢ 37 gr. 
Cupric chloride l2¢ 6 gr. 
Gum arabic 20 g 10 gr. 
Potassium bichromate 

sol., 1:48 2tol0ccm 1to5drops 


Water 7 1000 ccm 1 oz. 


272 PHOTOGRAPHIC FACTS AND FORMULAS 


2. Ferric ammonio-citrate, brown 12g 6 gr. 
Ferric oxalate 60 g 30 gr. 
Potassium oxalate 60 g 30 gr. 
Cupric chloride 12 ¢ 6 gr. 
Gum arabic 20 g 10 gr. 
Water 1000 ccm 1 oz. 

3. Ferric ammonio-citrate, brown 50¢ 25 St, 
Ferric oxalate 30 g LSigr: 
Potassium oxalate 70g 35 gr. 
Cupric chloride l6g 8 gr. 
Oxalic acid 30 g 15 gr. 
Silver nitrate 30 ¢ 15 gr. 
Gum arabic 20 g 10 gr. 
Water 1000 ccm 1 oz. 


Add potassium bichromate solution, 1:48, as desired. 

In preparing these solutions, mix in the above order, leave 
for 24 hours in the dark, and filter through cotton. Print 
faintly, and develop in: 


Silver nitrate 80 g 40 gr. 
Citric acid 20 ¢ 10 gr. 
Oxalic acid 16g 8 gr. 
Water 1000 ccm Logs 


Add sodium phosphate 3g (1% gr.) for blue-black tones. 
For use mix 1 part with 7 parts water. Fix in: 


Hypo 3to4g 24to 32 o0z. 
Water 1000 ccm 16 oz. 
For brown, blue-green, and other colours: 

A. Ferric ammonio-citrate, green 70g 35 gr. 
Ferric oxalate l6g 8 gr. 
Potassium oxalate l2¢ 6 gr. 
Oxalic acid 44 9 22281 
Uranium nitrate 40¢ 20 er. 


Gum arabic 20 g 10 gr. 


Hie TRON PROCESSES 


Water 1000 ccm 1 oz. 
Potassium bichromate 
solution, 1:48 6tol2ccm '\3to6drops 
Allow to stand 24 hours in the dark; then filter. 

B. Silver nitrate 100 g 50 gr. 
Citric acid 60 g 30 gr. 
Tartaric acid 20 g 10 gr. 
Water 1000 ccm 1 oz. 


IG) 


First coat the paper with A, and allow to dry; then coat with 
B. Print in the sun until the half tones are slightly tinted. 


For sepia tones wash and fix in: 


Salt 4¢ 12 gr. 

Hypo 4¢ Veer! 

Water 1000 cem 6 oz. 
For green tones immerse the print in: 

Potassium ferricyanide 3¢ 4 gr. 

Nitric acid 3 ccm 4 drops 

Water 1000 ccm 4 oz. 


Remove from this solution just before the green tone is 


reached, and fix in weak hypo. 


Platinotype 


This process is based on the light-sensitiveness of ferric 
oxalate, which is reduced by the action of light to ferrous 
oxalate, which dissolves in the alkaline oxalate used as a 
developer, thus reducing the platinum salt, used in the sensi- 
tiser, in situ; the iron salts form no part of the image. 

It is important that the ferric oxalate should be free from 
ferrous salt, and the most satisfactory way to ensure this is 
to prepare it. The following method should be adopted: 


Ammonia iron alum 520.2) Dioz. ao or 

Water 500 ccm 8 oz. 
Heat until dissolved, allow to cool slightly, and add: 

Ammonia 200 ccm 314 oz. 


Stir well for about 5 minutes. Then filter the solution, and 
wash the filter with repeated lots of water until the filtrate 
is no longer alkaline to litmus paper. Then dissolve in: 
Oxalic acid, pure 215¢ 1651 gr. 
Hot water 800 ccm 12 oz. 
Pour this solution over the filter repeatedly until all the 
ferric hydroxide is dissolved; wash the filter with sufficient 
water to make the volume of the solution 1000 ccm (16 0z.). 
An alternative method, which obviates the necessity of filter- 
ing, but takes longer, is to powder some iron alum, and 
weigh out the above quantities. Place the powder in a tall 
graduate; the tall metric cylindrical graduates are the most 
convenient. Pour on the powder the above quantity of am- 
monia mixed with an equal volume of water. Stir for a few 
minutes, and allow to stand for 10 minutes. Fill up the 
graduate with water, shake or stir well, allow to stand until 
the precipitate has somewhat subsided, and syphon off the 


274 . 


— > = \ 


PEALDINGO PY DE 275 


supernatant liquid. Repeat these operations until the liquid 
no longer turns red litmus paper blue. Finally, allow the 
precipitate to settle, and syphon off the water until the total 
bulk measures no more than 850ccm (13% 0z.). Add the 
oxalic acid dry, stir well for a few minutes until the solution 
clears up, then filter, and wash the filter with enough water 
to make the total bulk 1000 ccm (160z.). The result will be 
a 20 per cent solution of ferric oxalate with an excess of 1.2 
per cent of oxalic acid. The addition of the oxalic acid and 
the subsequent filtration must be effected by artificial light, 
not daylight, and the solution must be kept in the dark. Dry 
ferric oxalate, as obtainable commercially, is rarely suitable. 

Another stock solution required is a mixture of lead-iron 


- oxalate. This is made as follows: 


Lead acetate, pure 10 ¢ 154 gr. 

Water 100ccm 30z., 183 min. 
Dissolve by the aid of heat, and add: 

Oxalic acid, pure 4¢g 62 gr. 

Water 50 ccm? 1.0z., 330 min: 


A white precipitate of lead oxalate is formed, which should 
be collected on a filter, well washed with water, and dried. 
Add 1 part of the dry precipitate to 100 parts of the normal 
ferric oxalate solution, as given above. 

A stock solution of sodium ferric oxalate will also be 


required : 
Sodium ferric oxalate 500 g 3840 gr. 
Water 1000 ccm 16 oz. 


Shake until dissolved and filter. A stock solution of oxalic- 
gelatine will be required, but this will not keep more than 
3 or 4 days: 
Gelatine 10¢ 96 er. 
Water 100 ccm 2 oz. 


276 PHOTOGRAPHIC FACTS AND FORMULAS 


Allow to soak for 15 minutes, dissolve by heat, and add: 
Oxalic acid, pure 28 24 gr. 
There will be further required a 10 per cent solution of 
sodium platinum chloride (NaC1),.PtC1,.6H,O, and a 1 in 6 
solution of potassium chloroplatinite. All stock solutions 

must be kept in the dark. 

The best results are obtained with pure linen papers ; cheap 
wood-pulp papers will not give good results. While it is not 
absolutely essential with good papers, a preliminary sizing 
is desirable, and for this purpose gelatine, arrowroot, or 
tragacanth may be used. The disadvantage of gelatine is 
that it is very prone to form air bubbles, and arrowroot is 
preferable. To prepare the gelatine size, make a 2 per cent 
solution of gelatine in water, and add 1 per cent of alum. To 
make the arrowroot rub 20 g (154 gr.) into a thin cream with 
water, add to 1000 ccm (16 0z.) boiling water with constant 
stirring, and continue boiling for 5 minutes. Allow to cool, 
and remove the skin which forms on top. The gelatine size 
must be used warm. 

To apply the size, the paper should be pinned to a drawing 
board, or other flat surface at the corners and the size applied 
with a broad flat brush in straight strokes, first across and 
then up and down the paper, until the surface is uniformly 
wet. Then a round soft brush, a perfectly clean shaving 
brush being excellent, should be worked all over the surface 
until it appears even and begins to lose its gloss. It may 
then be hung up to dry. For rough drawing papers the sheets 
should be immersed in the size for from 5 to 30 minutes, 
according to the thickness of the paper, and the roughness 
of the surface. The paper should be drawn over the edge of 
the dish, so as to wipe off as much solution as possible, and 
then hung up to dry with the end that leaves the dish last at 
the top. 


BVALINOTYEE 277 


THE Cotp Batu Process.—To sensitise the paper it 
should be fastened by glass-headed push pins to a flat surface. 
with a sheet of blotting paper underneath. As it is important 
that the sensitising solution should not come into contact 
with the pins, it is advisable to provide the latter with guards, 
which can easily be prepared by cutting small squares of 
cardboard, turning up the edges, and passing the pins 
through the middle. As the paper expands and crinkles on 
application of the liquid, the pins may be removed, and the 
paper restretched and again pinned down. The sensitiser is: 


A. Potassium chloroplatinite sol. 3 ccm 50 min. 
Lead-iron sol. 4.5 ccm 75 min. 
Sodium chloroplatinate 7.5 drops 7.5 drops 
Water 3to8ccm 50 to 130 min. 

Or: 

B. Potassium chloroplatinite sol. 3 ccm 50 min. 
Lead-iron sol. 4.5 ccm 75 min. 
Oxalic-gelatine sol. 1 ccm 17 min. 
Sodium chloroplatinate 7.5 drops 7.5 drops 
Water 3to8ccm 50 to 130 min. 

Or: 

C. Potassium chloroplatinite sol. 3 ccm 50 min. 
Lead-iron sol. 3 ccm 50 min. 
Sodium ferric oxalate sol. 2ccm 33 min. 
Sodium chloroplatinate 7.5 drops 7.5 drops 
Water 3to8ccm 50 to 130 min. 


The quantity of water in each formula is dependent on the 
surface of the paper; smooth surfaces require less, rough 
ones the greater quantity. Increase of the water to 2 to 14 
times that given above gives grey prints. The above quantity 
of sensitiser is sufficient for 3750 qcm (580 sq. in.) of paper. 
Increase of the sodium chloroplatinate gives increased con- 
trasts, or an equal volume of a 10 per cent solution of 


278 PHOTOGRAPHIC FACTS AND FORMULAS 


potassium bichromate may be used instead. Omission of 
these naturally gives softer effects. Sensitiser A with arrow- 
root sizing tends to brownish-black tones, but with plain, not 
arrowroot-sized, drawing papers, black tones; with gelatine- 
sized papers blue-blacks are given. A and B give too hard 
prints with contrasty negatives; then C should be used, as 
this gives softer results. 

After printing until the image is faintly visible in greyish- 
violet against the pure yellow unprinted parts, the print 
should be rapidly and evenly immersed in either of the 
following developers: 


Neutral potassium oxalate 250 g 4 oz. 

Water 1000 ccm 16 oz. 
On: 

Neutral potassium oxalate 100 g 770 gr. 

Potassium phosphate 50 g 384 gr. 

Water 1000 ccm 16 oz. 


It is preferable to take hold of both ends of the paper, im- 
merse one end in the developer, face down, draw right 
through the solution and then turn face up. Development 
is comparatively slow and takes from 1 to 2 minutes; the 
dish should be gently rocked. As soon as sufficient depth is 
attained, immerse the print, without washing, in: 
Hydrochloric acid 20 ccm 154 min. 
Water 1000 ccm 16 oz. 
face downwards. The dish should be rocked. After 5 min- 
utes, remove the print to a second dish of water acidulated 
as above, and, after 15 minutes, remove to a third dish of 
half the above strength of acid. At the end of 15 minutes, 
place the print in running water for 30 minutes, then blot off 
between blotting papers, and dry. Dilution of the developer 
gives more brilliant prints; or the same result may be ob- 
tained by adding 2 to 5 per cent of a 1 per cent solution of 


PLATINOTY PE Zio 


potassium bichromate; but, in this case, printing must be 
carried further than usual. In place of the bichromate, 0.5 
to 1 per cent of ammonium persulphate may be used, which 
shortens the scale of gradation, and this is particularly useful 
in the case of over-printing or when thin flat negatives are 
used. 

SEPIA Paprer, Cotp BatHu.—Brown or sepia tones are 
readily obtained by the addition of a mercury salt to the 
sensitiser, and the best is mercuric citrate, prepared as fol- 
lows: 


Yellow mercuric oxide 5g 96 gr. 
rivic ‘acid :.” 25g 480 er. 
Water 100 ccm 4 oz. 
Heat until dissolved, and filter. The actual sensitiser is: 
Ferric oxalate sol. : 8 ccm 130 min. 
Potassium chloroplatinite sol. 4ccm 65 min. 
Mercuric citrate sol. lto4ccm 16 to 65 min. 
Sodium chloroplatinate 
sol. 2Zto5drops 2to5 drops 


This should be applied as described above and to the same 
area of paper. The best developer is one of the following: 
Neutral potassium 


oxalate 100to 300g 154to 462 gr. 
‘Water 1000 cem 16 oz. 

Or: 
Potassium oxalate 70 to 300g 538 to 2304 gr. 
Potassium phosphate 30 g 230 gr. 
Oxalic acid 10g 77 gr. 
Water 1000 ccm 16 oz. 


The stronger the developer, the more rapid its action and the 
softer the print; the more mercury salt used, the weaker 
should be the developer; with contrasty negatives and with 
less mercury, the stronger should be the developer. Prints 


280 PHOTOGRAPHIC FACTS AND FORMULAS 


should be developed for not less than 5 minutes. The acid 
baths should not be stronger than from 0.5 to 1 per cent; the 
acid treatment with the three baths should not last longer 
than 30 minutes in all. The smaller quantities of the mercury 
solution give the best colours. For this process the best 
results are obtained with paper sized with agar-agar, which 
may be prepared as follows: 

Agar-agar 10g 77 gr. 
Water 1000 ccm 16 oz. 
Soak for 24 hours with an occasional stir, then pour off the 
water, and add enough fresh water to make the total bulk 
to the above quantities. Heat until boiling, and allow to boil 
for 10 minutes; filter through a piece of well-washed linen, 
and allow to cool until a firm jelly is obtained. This jelly 
should be squeezed twice through coarse canvas, so as to 
divide it up into little nodules. A small quantity should be 
placed on the paper, worked all over with a fairly stiff brush, 
then equalised with circular strokes with a softer brush, and 
dried. The quantity used depends on the surface of the 

paper, but this should not be strongly glazed when dry. 
Tue Hot Batu Processes.—In this process a hot devel- 
oper is used and the sensitiser should be: 


Ferric oxalate sol. 6 ccm 42 min. 
Potassium chloroplatinite sol. 4ccm 28 min. 
Gelatine-oxalic sol. 1 ccm 7 min. 


Greater contrasts in the prints may be obtained by the addi- 
tion of 5 to 10 drops of sodium chloroplatinate solution or a 
1 per cent solution of potassium bichromate. The same 
developers as used for the cold bath papers may be used at a 
temperature of 50° to 75° C. (122° to 167° F.). For sepia 
tones the sensitiser should be: 

Ferric oxalate sol. 6 ccm 100 min. 

Potassium chloroplatinite sol. 4ccm 67 min. 


yee UNAS ever 281 


Mercuric chloride, 


5% sol. 0.2tolccm 3to17 min. 
Sodium chloroplatinate 2to10drops 2 to 10 drops 
Water 2to4ccm 33 to 6/ min. 


The quantity of water is as before regulated by the surface 
of the paper. The solution should be applied in the manner 
already described. The best developer for this paper is: 


Potassium oxalate 100 ¢g 770 gr. 
Potassium phosphate 50 g 380 gr. 
Citric acid 20 g 154 gr. 
Potassium chloride 10g 77 gr. 
Water 1000 ccm 16 oz. 


Use at a temperature of 70° C. (158° F.). 
CoLp Batu Paper (Lainer).— 


A. Ammonium ferric oxalate 50 g 134 oz. 
Water 58 ccm 2.025 
Oxalic acid, 10% sol. 8 ccm 150 min. 

B. Potassium chloroplatinite 2¢g 30 gr. 
Water 10 ccm 150 min. 

The sensitiser for 3352 qcm (520 sq. in.) should be: 
A solution 4 ccm 68 min. 
B solution 8 ccm 136 min. 
Potassium bichromate, 4% sol. 8ccm 136 min. 


Immerse the exposed print for from 1 to 3 minutes in the 
developer, special salts being supplied for this, until fully 
developed; then clear in four acid baths of hydrochloric acid, 
1:60, and wash for a short time in running water. For 
sepia prints the developer should be heated to 66° to 88° C. 
(150° to 190° F.), and the prints cleared in three acid baths 
of half the above strength. Development should be effected 
in a feeble white light. The addition of 2 to 4 drops of a 
10 per cent solution of potassium bichromate to the developer 
increases the brilliancy of the prints. 


282 PHOTOGRAPHIC FACTS AND FORMULAS 


PALLADIOTYPE PAPER.—This paper gives a very visible 
printing image, and exposure should be carried on until all 
details are visible. Immerse the prints face up in: 


Sodium citrate PEPE ew 10 oz. 
Citric acid PEA M 1 oz. 
Water 1000 ccm 43 oz. 


For black prints the temperature should be kept between 7° 
and 16° C. (45° to 60° F.). For sepia paper use: 


Sodium citrate 50 g 6 oz. 
Citric acid 2.6¢ 150 gr. 
Water 1000 ccm 120 oz. 


Heating the developer to 38° C. (100° F.), not beyond, gives 
warmer tones. Clearing bath for both papers: 


Sodium citrate 232.5 g 10 oz. 
Citric acid 93 g 4 oz. 
Water 1000 ccm 43 oz. 


For use mix 1 part with 7 parts water. Three baths should 
be used, with 10, 15, and 20 minutes in the first, second, and 
third baths respectively. For brilliant prints add from 4 to 6 
drops of a 10 per cent solution of potassium bichromate to 
the developer. Wash the prints in running water for 10 or 
15 minutes or in several changes of 10 minutes each. 
SATISTA PAPER.—Print until a faint image appears, and 


develop in: 
Potassium oxalate 200 g 8 oz. 
Oxalic acid 5.2 g 100 gr. 
Water 1000 ccm 40 oz. 


Temperature about 21° C. (70° F.); for warmer tones heat 
to 38° C. (100° F.). Clear the prints in: 


Sodium citrate 4g 1Y oz. 
Water 1000 ccm 75 oz. 


Three baths are advisable of 5, 10, and 15 minutes respec- 
tively, followed by a short washing for 10 minutes, not 





PULATINODY PE 283 


longer, in running water or several changes of water. Then 
fix in: 
Hypo 125 ¢ 6 oz. 
Water 1000 ccm 48 oz. 
for 15 minutes. Finally, wash in running water for 45 
minutes or in about 12 changes of water. The water used 
for the clearing bath must be free from lime. To free water 
from lime, dissolve oxalic acid 0.5 g (15 gr.) in 75 oz. (1000 
ccm). Allow to stand for some hours, and decant from the 
precipitate. 

THE PLATINUM-IN-DEVELOPER PrRocess.—A variation of 
the platinotype process consists in using either no, or very 
little, platinum in the sensitiser, and adding it to the devel- 
oper. For this arrowroot size gives the best results, and the 
paper should not be highly sized. The sensitising solution 
may be one of the following: 


A. Lead-iron sol. 5 ccm 80 min. 
Mercuric chloride, 5% sol. 0.2ccm 3 min. 
Water 3to6ccm 48 to 92 min. 

B. Lead-iron sol. 5 ccm 80 min. 
Potassium chloroplatinite sol. 0.5 ccm 8 min. 
Water 3to6ccm 48 to 92 min. 

C. Lead-iron sol. 5 ccm 80 min. 
Potassium chloroplatinite sol. 0.3 ccm 5 min. 
Sodium chloroplatinate sol. 0.4 ccm 6.5 min. 
Water 3to6ccm 48 to 92 min. 

D. Lead-iron sol. 5 ccm 80 min. 
Sodium chloroplatinate sol. 0.8ccm 13 min. 
Water 3to6ccm 48 to 92 min. 


A and B are suitable for normal negatives; C gives greater 
contrast ; and D should be used for very soft negatives. The 
area of paper is as previously stated. It is preferable to 


284 PHOTOGRAPHIC FACTS AND FORMULAS 


allow the paper to dry at normal temperatures. The devel- 
oper should be: 


Potassium oxalate lg 16 gr. 
Potassium chloroplatinite lg 16 gr. 
Potassium phosphate 0.5¢ 8 gr. 
Water 12 ccm 192 min. 
Glycerine 6 ccm 96 min. 


Place the print face up on a sheet of glass, and paint with 
the above, using a broad flat brush, and working as quickly 
as possible. For the above area of paper about 20ccm 
(154 min.) of developer will be required. 

For line work or black and white work, this process is 
very suitable, and the following sensitiser should be used: 


Lead-iron sol. 7.5 ccm 120 min. 
Potassium chloroplatinite 

sol. 0.375 ccm 6 min. 
Neutral potassium chromate, 

1% sol. 0.375 ccm 6 min. 
Water 7.5 ccm 120 min. 


The above quantity is sufficient for 5940 qcm (87/0 sq. in.). 
The best developer for this work is: 


Potassium chloroplatinite 12 ccm 84 min. 
Glycerine 50 ccm 350 min. 
Water 450 ccm 8 02z. 


Thirty ccm (1 0z.) should be used for the above area. Actu- 
ally, this process is as cheap as or cheaper than any silver 
printing process. The acid baths must be used with all 
papers as already described. 

PLATINUM PRINT-oUT PAPER.—It is possible to prepare 
platinum paper that will print out in the printing frame, but 
it does not keep well, and the results are greatly dependent 
on the humidity of the paper at the time of printing. If too 
dry, only the shadows will appear; while if too damp, flat 


BLATINOTYPRE 285 


foggy results are obtained. The stock solutions are: A, the 
normal potassium chloroplatinite solution; B, sodium ferric 
oxalate 50g (40z.), water 100ccm (80z.); C, gum arabic 
50g (40z.), water 100ccm (80z.). The sensitiser is: 


Potassium chloroplatinite sol. 4ccm 65 min. 
Sodium oxalate sol. 6 ccm 98 min. 
Gum sol. 4 ccm 65 min. 


Increased contrast may be obtained by the addition of sodium 
chloroplatinate or potassium bichromate solution as in the 
other processes. The paper must be dried quickly. Expos- 
ing the paper to steam after printing, if the image appears 
of sufficient depth only in the shadows, is of some assistance, 
but, at the best, it is not a satisfactory process. 

SEPIA ToNES BY DEVELOPMENT.—Ordinary hot bath paper 
may be developed to sepia by the use of the following devel- 
oper (Hubl): 


Potassium oxalate 100 g 768 gr. 
Potassium phosphate 50 g 384 gr. 
Citric acid 20 g 154 er. 
Potassium chloride 10g Shige, 
Mercuric chloride 10g 77 gr. 
Water 1000 ccm 16 oz. 


_ Use at a temperature of 80° C. (176° F.). Or the following 
may be used: 


Potassium oxalate 65 g 500 gr. 
Potassium citrate Ilg 85 gr. 
Citric acid l6g 123 gr. 
Mercuric chloride 6.75 g O20 
Water 1000 ccm 16 oz. 


Heat to 35° C. (95° F.). Or the following (Jacoby) may be 
used : 
Potassium oxalate 250 g 4 oz. 
Zinc oxalate 100 to 125g 800 to 1000 gr. 


286 PHOTOGRAPHIC FACTS AND FORMULAS 


Water 1000 ccm 16 oz. 
Heat to 21° to 28° C. (69° to 83° F.). The larger the 
quantity of zinc oxide the warmer the tone. Or: 


Potassium oxalate 200 g 31% oz. 
Acid ammonium phosphate 25 ¢g 200 gr. 
Cupric sulphate lg 8 gr. 
Water 1000 ccm 16 oz. 


The following complicated developer has also been recom- 
mended : 


A. Potassium oxalate 250 g 4 oz. 
Water 1000 ccm 16 oz. 
B. Cupric chloride 32 g 125 er. 
Water 1000 ccm 8 oz. 
C. Mercuric chloride 62.5 ¢ 1 oz. 
Water 1000 ccm 16 oz. 
D. Lead acetate l6¢g 32 gr. 
Water 1000 ccm 4 oz. 


Add 12 parts of A to 4 parts B, then 4 parts C to 1 part D, 
and heat until the precipitate first formed is redissolved. 
Use at a temperature of 80° C. (176° F.). 

Loca DEVELOPMENT.—By thickening the developer with 
glycerine, it is possible to develop cold-bath prints locally, 
so as to obtain various effects. Paint a sheet of glass larger 
than the print with glycerine, thinly and evenly. Use four 
teacups or saucers; fill A with pure glycerine; B, with 
glycerine 10 parts, saturated solution of potassium oxalate 
1 part; C, with glycerine 10 parts, saturated solution of 
potassium oxalate 5 parts; D, with saturated solution of 
potassium oxalate. Lay the print face up on the glycerined 
glass, and dab into contact with a pad of clean linen. Paint 
the whole of the print with the pure glycerine, using a long- 
handled soft brush, and allow to soak for 3 minutes. Sat- 
urate the brush with the B mixture and paint over the whole 


PLATINOTY PE 287 


print. Then charge the brush with C solution, and paint 
those parts which it is desired to bring out more than the 
rest. Finally, treat any desired part with D solution. The 
glycerine merely prevents any lines of demarcation showing. 
The subsequent acid bath treatment is as usual. | 

INTENSIFYING PLATINoTYPES.—Weak platinotype prints 
can be intensified, and, unless much under-printed, good re- 
sults are obtained. 

Silver intensification (Clarke)—This is extremely liable 
to give a coarse granular deposit, which makes it unsatisfac- 
tory on the whole: 

Glacial acetic acid 150 to 160 drops 50 to 60 drops 


Pyrogallol 2¢g |e ae 

Water 1000 ccm 16 oz. 
Dissolve, and add: 

Silver nitrate, 12% sol. 20drops 8 drops 


It is advisable to flood the print, which must be quite free 

from iron salts and acid, with the pyro solution, then to pour 

off the solution ; add the silver to it, again flood the print, and 

repeat until sufficient intensity is attained. Hydrochinon or 

metol may be used instead of the pyrogallol. The print 

should be well washed, and, finally, fixed in weak hypo. 
Intensification with platinum (V ogel).— 


Potassium oxalate developer 5ccm 80 min. 
Water 50 ccm 800 min. 
Potassium chloroplatinite 

sol. 3to5drops 3to5 drops 


This also tends to give coarse grain, and the whites are very 
apt to be stained. Far better results are obtained by the 
following (Hiibl) : 

A. Sodium formate, 10% sol. 

B. Platinum perchloride, 2% sol. 
For use add 5 parts A to 200 parts water, and then add 5 


288 PHOTOGRAPHIC FACTS AND FORMULAS 


parts B. Intensification will be complete in about 15 minutes. 

Intensifying with gold (Dollond).—The print should be 
placed face up on a sheet of glass, and, if previously dried, 
must be soaked in water first. Dab into flat contact with a 
clean linen pad, and paint the surface with glycerine, using 
a soft brush. Then pour on the surface a few drops of a 1.5 
per cent solution of gold chloride and paint rapidly over with 
the brush. As soon as the desired intensity is reached, rinse 
under the tap, and sponge back and front with a normal metol 
developer diluted with an equal volume of water. There is 
some danger of the white assuming a pink or blueish tint with 
this process. 

Toninc PLATINOTYPES.—Platinum prints can be toned 
with uranium, iron, and catechu. The first gives brownish- 
red tones, the second blue, and the third browns. For the 
uranium toning the following stock solutions are required: 


A. Uranium nitrate 100 g 768 gr. 
Glacial acetic acid 100 ccm 768 min. 
Water 1000 ccm 16 oz. 

B. Potassium ferricyanide 100 ccm 768 gr. 
Water 1000 ccm 16 oz. 

C. Ammonium sulphocyanide 500 g 3840 er. 
Water 1000 ccm 16 oz. 


For use add 10 ccm A to 1000 ccm water (77 min. to 16 oz.) ; 
then add 10 ccm (77 min.) C and, finally, 10 ccm (77 min.) 
B. Instead of the sulphocyanide, 5ccm (35 min.) of a 10 
per cent solution of sodium sulphite may be used. The well- 
washed print should be placed in a dish, well flooded with 
plenty of the solution, and the dish rocked until the desired 
tone is obtained. On the slightest sign of the solution becom- 
ing cloudy, pour off and apply fresh; otherwise the whites 
will be stained. 
The iron toning requires: 


PLATINOTYPE 289 


C. Ammonia iron alum 100 g 768 gr. 
Hydrochloric acid 100 ccm 768 min. 
Water 1000 ccm 16 oz. 


For use add 5ccm (35 min.) A to 1000 ccm (16 0z.) water, 
then 2ccm (14min.) B, and, finally, 5cem (35 min.) C. 
Both these baths, particularly the uranium, intensify the 
prints. 

The catechu toning process (Packham) gives warm brown 
tones, but it is difficult to keep the whites pure; on the other 
hand, this is rather effective than otherwise, as the print ap- 
pears as if prepared on toned paper. A stock solution is 
prepared of: 


Catechu 782 600 gr. 

Water 1000 ccm 16 oz. 
Boil for 5 minutes in a glass or porcelain vessel, and add: 

Alcohol 200 ccm Sal foros 
For use mix: 

Stock solution 2.5 ccm 20 min. 

Water. 1000 ccm 16 oz. 


When used cold, this takes some hours to tone, but, by rais- 
ing the temperature to 55° to 64° C. (130° to 147° F.), only 
about 15 minutes is necessary. Should the whites be stained, 
and it is desired to remove this, soak in: 


Castile soap 9g 69 gr. 
Sodium carbonate, cryst. 18g 138 gr. 
Water 1000 ccm 16 oz. 


When the stain is reduced, wash and dry. 
Copper Toninc (Menke)—Four stock solutions are re- 


quired : 
A. Cupric sulphate 4lg 38.5 gr. 
Water 1000 ccm 16 oz. 
B. Potassium ferricyanide 35.7 g 274 gr. 


Water 1000 ccm 16 oz. 


290 PHOTOGRAPHIC FACTS AND FORMULAS 


C. Potassium citrate, sat. sol. 
D. Potassium sulphocyanide 100 g 768 gr. 
Water 1000 ccm 16 oz. 
For use mix in the following order: A 140 parts, B 140 parts, 
C 24 parts, D 50 parts. As this is nothing more than a 
modification of the copper toning process for bromides, pre- 
sumably the same class of tones will be obtained. 
BLUE PRINTS BY DEVELOPMENT (Waverley) .— 


Potassium oxalate, 1:3 sol. 22 ccm 170 min. 
Potassium ferricyanide, 

10% sol. 9 ccm 70 min. 
Glycerine 55 ccm 42 min. 
Water 1000 ccm 16 oz. 


Printing must be carried deeper than usual. The prints as- 
sume a green tone in the developer and only turn blue in the 
acid baths. 

PRINT-OUT SEPIA PapER.—Another method of obtaining 
pure brown tones is by the admixture of some palladium salt 
with the sensitiser, potassium chloropalladite in 10 per cent 
solution being used. The paper should preferably be sized 
with arrowroot, and the sensitiser is: 


Potassium chloropalladite sol. 4ccm 65 min. 
Sodium ferric oxalate 6 ccm 97 min. 
Lead-iron sol. 2cecm 32 min. 
Water 3to6ccm 45 to 96 min. 


The image is so slightly visible that an actinometer should be 
used. Development should be effected with steam or by 
pressing the prints between damp blotting papers. 

Another method is by the use of mercury (Pizzighelli) : 


A. Potassium chloroplatinite 10¢g 70 gr. 
Water 60 ccm 420 min. 
B. Sodium ferric oxalate 40 ¢ 280 gr. 


Gum arabic 40g 280 gr. 


Rien LINGO DYE 291 


Sodium oxalate, 3% sol. 100 ccm 700 min. 
Glycerine 3 ccm 21 min. 
Potassium chlorate 0.5 g Jele Sy gf 


Heat the sodium oxalate solution to 40° to 50° C. (104° to 
122° F.), add the iron salt, the chlorate, and the glycerine; 

pour on to the gum, rub until dissolved, and strain through 

linen. The chlorate can with advantage be replaced by about 

10 to 20 drops of 1 per cent solution of potassium chromate. 
C. Mercuric chloride, 5% sol. 20ccm 140 min. 


Sodium oxalate, 3% sol. 40 ccm 280 min. 
Gum arabic 20 ccm 140 min. 
Glycerine 1.8 ccm 12.5 min. 


This is prepared in the same way as B. For sensitising 
2000 qcm (310 sq.in.) use: 


Solution A 5 ccm 35 min. 

Solution B 4 ccm 28 min. 

Solution C 4 ccm 28 min. 
The following may also be used (Watzek) : 

Sodium ferric oxalate 10 ccm 160 min. 

Potassium chloroplatinite 6 ccm 92 min. 

Mercuric chloride 5 drops 5 drops 


Add a few drops of 1 per cent solution of potassium bichro- 
mate to obtain contrasts. The other salts should be saturated 
solutions at 18° C. (64° F.). The paper should be sized 
with starch or arrowroot, two to three coats being used. 
Printing is continued until the desired depth is reached. 
RESTORING PLATINOTYPES.—Sometimes through insuffi- 
cient washing the paper of platinotypes yellows with age, due 
to the action of the air on the residue of iron salts. This 
stain can be removed by treatment with a weak solution of 
chloride of lime or eau de Javelle. Make a saturated solu- 
tion of chloride of lime in water, filter, and add 1 part of the 
clear solution to 100 parts of water, then add dilute hydro- 


292 PHOTOGRAPHIC FACTS AND FORMULAS 


chloric acid until there is a faint smell of chlorine. Or mix 
1 part of chloride of lime with 1 part of sodium carbonate 
and 10 parts water, stir well, filter or decant the clear solu- 
tion, add 90 parts water, and faintly acidulate as above. Im- 
merse the stained print in either of these solutions until 
bleached; then wash and dry. This treatment cannot affect 
the image. 

VARNISHING PLATINUM PrINTS.—Frequently platino- 
types appear rather dull and sunken-in compared to their 
appearance when wet. Application of print varnishes will 
then brighten them up; but the surface should not appear 
glossy. Artist’s size, diluted with warm water, may be used; 
or megilp may be used in the same way; or the print may be 
sprayed or lightly painted with 1 part of mastic varnish 
diluted with 8 parts alcohol. For stronger effects ordinary 
negative varnish may be applied locally or generally with a 
brush. Or a solution of gelatine, about 4 per cent, may be 
made, the print bodily immersed in this while warm, and 
hung up to dry. Or the print may be rubbed with en- 
caustic paste. 

PLATINUM ResipuEs.—The high cost of platinum makes 
it well worth while to save all platinum residues. Scraps of 
paper, if unexposed, should be exposed to daylight and 
developed in the usual way. Print trimmings should be 
burnt, the scraps of the paper previously dealt with being 
mixed with them. The developer should be mixed with one- 
fourth its volume of saturated solution of ferrous sulphate, 
boiled, and the platinum precipitate allowed to settle or be 
filtered out. The first and second acid baths should also be 
saved, boiled down until of convenient bulk, at least one- 
fourth their original volume, and scrap zinc added. Black 
platinum is precipitated, and may be collected on a filter. 
It is not worth while to make the residues into platinum salts, 


PEATINO TYPE 293 


but the residues should be sent to a refiner, who will allow 
cash for them, with the deduction of a small fee for refin- 
ing. An alternative plan is to mix the developing and acid 
baths, and immerse sheets of clean copper therein, when the 
platinum will be deposited on the copper as a precipitate. 
The platinum deposited on the copper can be scraped off, and 
mixed with the precipitated metal. 
PLATINO-URANOTYPE.—A little-used process (Reynolds). 
Two stock solutions are required: 
A. Uranium chloride, sat. sol. 


B. Potassium chloroplatinite 4¢ 60 gr. 
Water 48 ccm LY, oz. 


Mix in equal volumes, paint over well-sized paper, and 
rapidly dry. Potassium chlorate may be added to increase 
contrast. Print until only a faint trace of an image is visible, 
and develop on a ferrous oxalate developer. Wash the prints 
in three successive baths of hydrochloric acid, about 1% per 
cent, wash, and dry. 

MERCURO-URANOTYPE.— Very little used (Reynolds). Two 
stock solutions are required: 

A. Saturated solution of uranium chloride 

B. Saturated solution of mercuric chloride 
For use mix 8 parts A with 1 part B and apply to paper. 
Expose until the image is seen in full strength, then float on 
a dilute solution of chloride of gold or potassium chloro- 
platinite. Wash in water acidified with hydrochloric acid, 
wash and dry. The toning may be omitted when warmer 
tones are obtained. 

PALLADIOTYPE.—Coat paper with uranium chloride, ferric 
oxalate, or sodium ferric oxalate, or a mixture of all three. 
Expose until the image is faintly visible; then float the print 
on: 


294 PHOTOGRAPHIC FACTS AND FORMULAS 


Potassium chloropalladite lg 1 gr. 
Water 500 ccm 1 oz. 
Or paint this over the print, wash in acidulated water, then 
in water, and dry. The image is somewhat similar to platino- 
type, but of a warmer colour. 

To DistiInGuIsH A BROMIDE FROM A PLATINUM PRINT.— 
Touch a small corner of the print with a saturated solution 
of mercuric chloride, or a 10 per cent solution of potassium 
cyanide. In the first case, the bromide image is bleached, 
and, in the second, the bromide image is dissolved; platinum 
images are unaffected. 





Ozotype and Allied Processes 


OzotyPE Process.—This process is based on the transfer 
of the hardening effect of a chromate salt formed by exposure 
to light in the presence of a colloid, to another film containing 
a pigment. 

A well-sized paper should be chosen, or be sized with a 
2 per cent solution of gelatine. With rough or absorbent 
papers it may be necessary to give two or three coats, allow- 
ing to dry after each. Or the following may be used: 


Soluble starch 100 g 768 gr. 

Water 200 ccm 4 oz. 
Rub into a cream, and add to: 

Boiling water 800 ccm MOL 


Allow to boil for 5 minutes, then filter through thick linen, 
and add: 
Formaldehyde 50 ccm 25 min. 
Alum 0.5 ¢ 3.8 gr. 
An almost clear solution that keeps well should result. Pin 
the paper to a board, and with a pad or flat brush paint the 
surface until it appears uniformly wet. Papers with very 
smooth surfaces may be floated on the above, diluted with an 
equal volume of water, or a 10 per cent solution of fish glue 
may be used in the same way. The paper must be thoroughly 
dried. The sensitising solution may be (Manly): 


Potassium bichromate 50 g 384 gr. 

Manganese sulphate 50 g 384 gr. 

Water 1000 ccm 16 oz. 
Or (Hiibl): 

Potassium bichromate 60 g 460 gr. 

Manganese sulphate 30 g 230 gr. 


295 


296 PHOTOGRAPHIC FACTS AND FORMULAS 


Alum 20 g 154 gr. 
Boric acid 30 g 230 gr. 
Water 1000 ccm 16 oz. 


It is as well to add to this a few drops of fish glue. A piece 
of linen or Canton flannel should be wrapped round a reason- 
ably large pad of absorbent cotton, some of the above solu- 
tion poured on to the middle of the paper, evenly distributed 
with the pad, and then the paper hung up to dry in the dark. 
The exposure will be from 3 to 5 minutes in summer, and 
from 15 to 25 minutes in winter. The paper should then be 
washed in water, but too long washing must be avoided. 

A piece of pigment tissue, the same size as the paper, 
should be immersed in the following: 


Hydrochloric acid 2 ccm 15 min. 
Ferrous sulphate 3.02 27 gr. 
Water 1000 ccm 16 oz. 


This is suitable for normal pictures; for contrasty prints 
reduce the iron salt to 2.5g (19 gr.); and for soft prints 
increase to 4.5g¢ (35 gr.). When the tissue is quite limp, 
immerse the print in the bath, bring the two surfaces into 
contact, lift out together, squeegee into close contact, and 
leave for from 30 to 60 minutes, the longer time giving 
greater detail in the prints. Development may be effected 
at once, or delayed for some hours if more convenient. 

A later procedure required the following stock solutions: 


A. Hydrochloric acid 28 ccm Loz 
Cupric sulphate 31 ccm 480 gr. 
Water 560 ccm 20 oz. 

The working solution was composed of : 
Hydrochinon 0.6¢ 9 gr. 
Water 1130 ccm 40 oz. 
Solution A 14 to 28 ccm Y, to 1 oz. 


For soft pictures of small size from hard negatives, use the 


Peery eAND, ALLIED PROGHSSES —°297 


lesser quantity of A; for normal negatives use 21 ccm 
(34 oz.) ; and for large prints from soft negatives use the full 
quantity of A. The pigment tissue should be immersed in 
the above for 30 seconds, the print also immersed therein 
and brought into contact face to face, lifted out, thoroughly 
squeegeed, and left in contact as advised for the first bath. 
If the two are left in contact for more than 1% hours, they 
should be afterwards immersed in cold water for from 30 to 
45 minutes. Development may be effected as in the carbon 
process with water from 43° to 46° C. (109° to 115° F.). As 
soon as development is complete, the print should be im- 
mersed in a 5 per cent solution of alum or: 


Alum 28 g 1 oz. 
Hydrochloric acid 1.7 ccm 30 min. 
Hydrochinon 0.6¢g 10 er. 
Water 560 ccm 20 oz. 


for the same time, and then washed. 

OzoproMeE.—In this process, pigmented tissue impregnated 
with a bichromate and ferricyanide is brought into contact 
with a bromide print. The metallic silver reduces these com- 
pounds, and the gelatine is hardened in contact with the 
silver, so that it becomes insoluble in hot water, just as 
though it had been exposed to light. Practically, it is a 
carbon process, in which chemical action does the work of 
light; it is, therefore, possible to carry out the process at 
night, and many carbon prints may be obtained from one 
bromide, if thought desirable. 

Any good bromide print may be used; but the best results 
are obtained with those not on baryta-coated paper. The 
print should be first hardened by immersion for 5 to 10 
minutes in a 5 per cent solution of alum, or formaldehyde, 
or a 4 per cent chrome alum solution, washed, and dried. The 
ozobrome or sensitising solution is as follows (Manly) : 


298 PHOTOGRAPHIC FACTS AND FORMULAS 


Potassium bichromate 6g 46 er. 
Potassium ferricyanide 6g 46 gr. 
Potassium bromide 6g 46 er. 
Alum 3¢g 23 or, 
Citric acid lg / gr. 
Water 1000 ccm 16 oz. 
Or (Schmidt) : 
Potassium bichromate 8g 61 gr. 
Potassium ferricyanide 10 ¢ 77 gr. 
Potassium bromide 7g 54 er. 
Alum lg 7d 2. 
Citric acid 0.5 ¢ 3.8 gr. 
Water 1000 ccm 16 oz. 
Or (Faworsk1) : 
Potassium bichromate 8.3 g 64 gr. 
Potassium ferricyanide 6.6 g 51 gr. 
Potassium bromide 6.6 g Shor, 
Chrome alum 3g 23 gr. 
Citric acid lg 7./ gr. 
Water 1000 ccm 16 oz. 


In hot weather the addition of 1 per cent of magnesium 
sulphate to the above baths is advantageous; or of (Namias) : 


Chromic acid 5g 38.5 gr. 
Potassium bromide 20 g 154 gr. 
Water 1000 ccm 16 oz. 


The bromide print should be immersed in cold water for 10 
minutes, and placed face up on a sheet of glass. The pig- 
ment tissue should be soaked in 1 part of the ozobrome solu- 
tion diluted with from 4 to 5 parts of water for 2 to 3 min- 
utes, and then transferred to an acid bath. This is preferably 
kept as a stock solution: 

Chrome alum 100 g 768 gr. 





Pox r Ee AND ALLIED PROCESSES 299 


Oxalic acid 20 g 154 er. 
Water 1000 ccm 16 oz. 

For use mix 150 parts with 850 parts of water, and add 1.2 
parts citric acid. This last addition is not essential, but it 
keeps the whites cleaner. In this acid bath the tissue should be 
allowed to remain not longer than 7 to 15 seconds, then drawn 
once or twice over the surface of clean water, and squeegeed 
into contact with the wet bromide print. The two should be 
left under light pressure for about 15 minutes, and can then 
be developed like an ordinary carbon print with water at 
40° to 45 C. (104° to 113° F.). Then the print should be 
fixed in hypo and ferricyanide to remove the silver, washed, 
and dried. In this case, the bromide print forms the basis of 
the carbon print. In the alternative or transfer process, the 
bromide print is stripped from the pigment tissue, the latter 
squeegeed into contact with transfer paper, and developed 
as usual. The procedure is precisely the same up to the point 
of development. At this point, the print and the adherent 
tissue are immersed in water for 1 minute, the print pulled 
off, and immersed in a dish of water. The carbon tissue is 
squeegeed into contact with transfer paper, which has been 
soaked in water for about 15 minutes, and then treated as in 
the carbon process. The bromide print should be well washed 
for 30 minutes, then immersed in daylight in an ordinary 
developer until fully developed, then washed, and dried. It 
can be repeatedly used in this way. It is obvious that en- 
largements may be treated in this way. 

CarBro Process.—This is practically the ozobrome pro- 
cess. Two stock solutions are required: 


A. Potassium bichromate 50 g 1 oz. 
Potassium ferricyanide 50 g 1 oz. 
Potassium bromide 50 g 1 oz. 


Water 1000 ccm 20 oz. 


300 PHOTOGRAPHIC FACTS AND FORMULAS 


B. Glacial acetic acid 50 ccm 1 oz. 
Hydrochloric acid, pure 50 ccm 1 oz. 
Formaldehyde 1100 ccm 22 oz. 

The working solutions are: 
First bath. A solution 1 part 
Water 3 parts 
Second bath. B solution 1 part 
Water 32 parts 


The first bath may be repeatedly used, but the second should 
be made fresh every time. The temperature is important, 
and 18° C. (65° F.) is convenient. The bromide print must 
be thoroughly and evenly soaked in water. The tissue should 
be immersed in the first bath for 3 minutes, and transferred 
to the second bath. The length of stay in this determines 
the character of the resultant print. If the final print is to be 
like the bromide, 20 seconds would be correct; a shorter 
time gives increased contrasts, a longer time softer prints. 
The actual time varies with different makes of bromide paper, 
but the above rules apply to all. The soaked tissue is removed 
from the second bath, squeegeed into contact with the wet 
bromide print, and the two left in contact for about 15 min- 
utes. A longer time gives a darker print. The tissue, after 
the lapse of the necessary time, is stripped from the bromide 
print, and the latter put into a dish of water to wash. The 
tissue should be brought into contact with a well-soaked sheet 
of transfer paper, thoroughly squeegeed, allowed to remain 
30 minutes, and then developed as in the carbon process. A 
lower temperature of the developing water should be started 
with; hotter may be used as development proceeds, if neces- 
sary. Almost any kind of bromide paper may be used; but 
development (gaslight) papers are less satisfactory. After 
the bromide print has been well washed, it can be developed 
in white light with any developer. It is advisable for the 







; Rue ore 


poe YPE AND ALLIED PROCESSES 301 


ffusion process, and this ies place sideways as et as 
¢ Jownwards. 


ri 


yah 


Oil and Bromoil 


BromoiL.—The most suitable bromide papers for this pro- 
cess are those with fairly thick emulsion films, with smooth 
or half matt surfaces which have not been hardened in the 
manufacture. Many firms make special papers for this work. 
A method of testing paper is to cut a strip, fix, wash, and dry 
as usual ; then immerse in water at 25° C. (77° F.), gradually 
raise the temperature, and note when the film begins to feel 
slimy or slippery. This should be between 30° and 35° C. 
(86° and 95° F.); if higher than this, the gelatine has been 
hardened during manufacture, and is unsuitable for the pur- 
pose, or will require higher temperatures for the solutions 
than the usual ones, which range from 24° to 28° C. (75° to 
82° F.). Any developer can be used, though the least suit- 
able is pyrogallol, and the best temperature for development 
is 18° C. (65° F.). The prints should be well exposed and 
development carried to the limit, that is to say, until there 
is no longer any further accretion of density. The print 
should be rinsed two or three times with water and preferably 
fixed in a 30 per cent solution of hypo, containing 3 per cent 
potassium metabisulphite. Alum or chrome alum hypo baths 
are unsuitable. Washing should be carried out as usual. 
Some adherents of this process insist on the absolute neces- 
sity of drying the prints, while others consider it detrimental. 
The necessity, or otherwise, of this step depends on the 
character of the gelatine; soft gelatines require drying, while 
harder ones can be worked up at once. 

As will be seen from the following tables, there is a wide 
choice of bleaching and relief-forming baths. Those contain- 
ing copper salts are the most favoured. The most convenient 


302 


OIL AND BROMOIL 303 


way of making these bleachers is to keep the ingredients in 
separate 10 per cent stock solutions, and mix as required. 
The best results are obtained with freshly made prints. Old 
prints should be soaked in water at 20° to 25° C. (68° to 
77° F.) until quite limp, or the bleaching bath should be 
raised to these temperatures. Fresh solution should be used; 
repeated use of the same solution leads to irregularities. 
Bleaching may take from 5 to 30 minutes, according to 
temperature and composition of the bath. With those baths 
containing potassium ferricyanide, a subsequent treatment 
with 5 per cent sulphuric acid is advisable. After bleaching 
the print should be washed and fixed in a 10 per cent hypo 
solution containing 21% per cent sulphite, or 15 per cent hypo 
with 114 per cent metabisulphite. If there is any sign of a 
coloured residue in the image, especially in the shadows, it 
may be removed by treatment with 214 per cent sulphuric 
acid, and the print washed, or the following may be used: 


Thiocarbamide 25g 192 gr. 
Ammonium persulphate 25g 192 gr. 
Water 1000 ccm 16 oz. 


The prints should be washed for about ten minutes, then laid 
face up on a sheet of glass, the surface gently dabbed with a 
soft linen pad to remove any surface moisture, and should 
then be dried. 


BLEACHING Batus.— 


1 2 3 4 5 6 yf 8 
Potassium bichromate 22.5 18.2 10 8 0 8 10 29.5 
Potassium bromide 11.25 10.0 oe 7 10.3 15 3 
Potassium ferricyanide 11.25 10 20 10 2.3 10 3 59 
Potash alum 45 36.4 10 0.5 ae 40 10 ae 
Ammonium alum ate ahs 20. on 
Citric acid 11.25 10 aA il se 
Salt =A oh 53 
Glacial acetic acid at ae 7—14 


Hydrochloric acid A an 3 15 1 es 
1. Hewitt; 2. Rennie; 3. Weissermel; 4. Schmidt; 5. Garner; 6. Rennie; 
7. Rennie; 8. Quentin. 


After the print has been bleached in the above baths, it should be immersed 
in a 5 per cent solution of sulphuric acid for 5 minutes, and then washed. 


304 PHOTOGRAPHIC FACTS AND FORMULAS 


1 2 3 4 5 6 
Chromic acid 5 1.4 PA 2 1-2 2 
Potassium bromide 20 14 19.8 18 20 30 
Cupric sulphate zi 28 33 30 30 18 


1. Namias; 2. Smith; 8. Anon.; 4. Schrott; 5. Wurm-Reitmayer; 6. Duvivier. 


W228 4 4776 6 00 "Bees 10 Ply te 


Cupric sulphate 90 12 .. 40 43 40 22 30 °9:2 10:45 4ie 20 
Cupric bromide ae ee O ba eubners ANDAs Oe a a A 
Potassium bromide 10 8... 40 48 20 20 80°9-2510451U5e20 
Potassium bichromate 10 2 a ene 5 1,490 ieee 82 22aoer 0.8 
Potash alum Fife ea Sc PAE ace cies ee Oe are rf a 
Chrome alum tag hE Cchod © Rhee hones «oct tele’) Ueto idle 8) ate een 2 
Sulphuric acid Sr ae igttne to mune ie eres vet vee tao OLB ap O1 Gas mmm ras 
Glacial acetic acid Siren a nate MAEM SS 542 eer Ove He one at 
Potassium chromate GH Packers Goa) Moke mmets } owt Ca tarcu seme ah Lids. 


1. A. B. W.; 2. Mortimer; 3. Ermen; 4. Namias; 5. Seeman; 6. Brum de 
Canto; 7. Bendorf; 8. Weissermel; 9. Featherstone; 10. Featherstone; 11. 
Gillin; 12. Wellington & Ward. 


1 2 3 4 5 6 vf 8 9 10 11 
Cupric sulphate 29 28 30 24 7.6 15.18). 103725942 Saeed 
Potassium bromide 29 82 30 20 5 10 18 8 25 a oe 
Potassium bichromate 4.6 .. .. .- S75 ie 3 1 5 1.52 
Ammonium bichromate .. 4 5 10 EPP rr AIS Oris ate 47 
Hydrochloric acid 0:46 0.4 0.5 1.5 1 2 1 6.68 1.0 
Sulphuric acid AS heey Tee iis Po aoe A, Seaton ; 0.5 


Potash alum ae Pema Baked 25 & a puld aia Bolte eerie iD ia ie 
Salt ae Sho eylite soitens MPs os ete Ga CES 13.5 
1. Mayer; 2. Karpinski; 3. Tolkowsky; 4. Switkowski; 5. Birmingham Phot. 


Co.; 6. Rennie; 7. Mayer; 8. Namias; 9. Sturenburg; 10. Garner; 11. Swit- 
kowski. 


The quantities of the ingredients given in the above tables 
(Mebes) are for a total volume of 1000 parts of solution. 

The dried print may be soaked either in water, or a 2Y% to 
5 per cent solution of sulphuric acid for about 5 minutes, and 
then washed. The surface moisture should be blotted off 
and inking proceeded with. Dilute alkaline solutions may also 
be used, about 1 per cent caustic potash, soda or ammonia, 
5 per cent of the carbonates, or 10 per cent salt or calcium 
chloride. The print should be placed face up on a sheet or 
two of wet blotting paper, supported on a sheet of glass, and 
dabbed with a linen pad. Special brushes and inks are ob- 
tainable for this process, or the ink may be applied with a 
velvet roller. The inks may be obtained in almost every 


~~ ed 


OIL AND BROMOIL 305 


colour, and either the special inks, or lithographic, or photo- 
gravure inks may be used. Artist’s powder colours may also 
be used, and worked up on a slab with a palette knife with 
medium, boiled linseed oil, or raw oil with a little japanner’s 
gold size. The inks dry very slowly, and it has been sug- 
gested to treat the completed print with certain solvents for 
the medium, such as benzol, benzol and alcohol, petroleum 
ether, gasoline, etc. These are dangerous, and the best is 
carbon tetrachloride. The print is rinsed once or twice with 
the solvent, and then dried. This treatment gives a somewhat 
dead appearance in the shadows; then ordinary celluloid 
varnish, diluted with 2 to 3 parts of amyl acetate may be used, 
the prints immersed therein for a minute, and dried. 

Ort Printinc.—This is a process worked out by G. H. 
Rawlins, which is practically based on the older processes of 
Poitevin and Mariot. Gelatinised paper is sensitised with a 
bichromate, exposed under a negative, thoroughly washed, 
soaked in water for an hour, and then inked up, either with 
a roller or brushes, charged with greasy ink, which only takes 
on the exposed parts. 

Special papers, pigmoil or oil printing, can be obtained 
commercially; or paper may be floated on a 6 per cent solu- 
tion of soft collotype gelatine for a few minutes and hung up 
to dry. It should be sensitised with the following: 

Ammonium bichromate 60 g 460 er. 

Water 1000 ccm 16 oz. 
For use mix 1 part stock solution with 2 parts denatured 
alcohol. Place the paper face up on a flat board or sheet of 
glass, and apply the sensitiser freely with a pad of absorbent 
cotton or soft linen, a flat brush or a Blanchard brush. The 
alcoholic solution will not keep. The paper may also be 
immersed in a 5 per cent solution of ammonium bichromate 


306 PHOTOGRAPHIC FACTS AND FORMULAS 


for five minutes and dried. After exposure the image 
should be seen in a brown colour on the yellow ground of the 
paper, and should be rapidly washed until all trace of the 
sensitiser is removed. Then it should be allowed to soak in 
water at 25° to 28° C. (77° to 82° F.) for 10 minutes, placed 
face up on a damp pad or sheet of glass, the surface moisture 
removed, and the ink applied. The further treatment is as for 
the bromoil process. 

AQUARELLE PRINTING.—The preparation of the prints is 
exactly the same as for oil printing, but, instead of using oil 
pigments, thick water colour pigments are used. 

OrILoGRAPH.—This is a modification of the bromoil pro- 
cess, in which a plain gelatine paper is used. A good bromide 
print is soaked in water for 5 minutes, then squeegeed into 
contact with the gelatinised paper, which has been soaked for 
2 to 24% minutes at 16° C. (60° F.) in the following: 


Potassium bichromate ll¢g 84 er. 
Potassium ferricyanide 7528 58 gr. 
Potassium bisulphate 0.625 g 3 gr. 
Potassium bromide 7.52 58 gr. 
Chrome alum 16g 11 gr. 
Water 1000 ccm 16 oz. 


The print and the paper should be allowed to remain in con- 
tact under slight pressure for 20 minutes, then separated, and 
the print washed, when it can be redeveloped and used again. 
The gelatine-coated paper, after stripping, is placed in water 
at 32° C. (90° F.) for a few minutes; then a relief begins to 
show, and it can be inked up as usual. Either single or double 
transfer carbon paper may be used for the gelatinised paper. 

Maxkinc Bromoit TRANSFERS.—Presses are obtainable 
commercially, which practically consist of two superimposed 
rollers, with flat beds on each side for supporting the transfer 


OIL AND BROMOIL 307 


pads. It is possible to use an old print burnisher, but the 
gears interlocking the two rollers should be removed so that 
the lower roller is driven by the pressure only. Or the 
domestic wringer, with rubber or hard wood rollers may be 
used. A very simple means of obtaining transfers was sug- 
gested by Minuth, which consists of rubbing instead of 
rolling, using a hardwood tool, shaped as shown in Fig. 6, 





Fig. 6 


practically a wooden chisel with rounded edge. The rub- 
bing should not be done direct on the bromoil, but prefer- 
ably on a sheet of waxed paper, and this may also be 
used for masks to keep the margins of the paper clean. 
Registration pins are also useful, especially in multiple trans- 
fer. These can be made by passing a flat-headed drawing pin 
through a piece of thin cardboard about 214 x 2¥ inches, and 
then gluing another piece of card on the back of the first one 
so as to cover the head of the pin. When dry the cards are 
cut as close to the head of the pin as possible. Two of these 
should be made. Two holes should be punched through the 
bromoil at opposite sides, and the back and front of the print, 


308 PHOTOGRAPHIC FACTS AND FORMULAS 


just around these holes, painted with celluloid varnish. This 
is to prevent the absorption of water around the holes, so that 
they will not be deformed and thus cause non-registration 
in subsequent printings. 

Any paper may be used to transfer to, but the soft copper- 
plate or collotype papers are the best, as they absorb the ink 
slightly and give a more velvety appearance. It is important 
that the paper be lightly sized, otherwise the surface may 
tear in patches. A good size can be made by boiling 2 per 
cent of starch in water, and this can be painted over the 
surface with a flat brush. Too much size prevents transfer. 
Hard, thick papers may be soaked in water and placed be- 
tween thick fluffless blotters under light pressure for a little 
time to even the dampness. 

Fig. 7 shows the laying of the transfer paper on the marked 





Fig. 7 


bromoil and the method of fitting the pins. A, B in Fig. 7 
show the correct way to hold the tool and C the correct angle 
for this. The strokes may be either elongated ovals as in A, 


OIL AND BROMOIL 309 


Fig. 8, or zig-zag lines as in B. While rubbing, the paper 
should be held ‘firmly down with the other hand close to the 
tool. It is preferable to use a normal relief and a soft ink 
rather than a hard one and high relief. When two transfers 
are to be made on the same paper it is advisable to dust the 





Fig. 8 


first with talcum powder. Care must be taken in fitting the 
paper on the registration pins; one should be fitted first into 
the hole and a cork slipped over it to prevent the paper slip- 
ping off and then the other fitted into place. In using this 
transfer process for three-colour work care must be taken to 
keep everything at as even a temperature as possible. It is 
advisable also to mark around two corners of the bromoil 
with pencil lines, which with the pins facilitates registration. 
A sheet of thin celluloid should be placed over the print and 
the outlines of a few prominent objects traced on the cellu- 


310 PHOTOGRAPHIC FACTS AND FORMULAS 


loid, and without shifting the celluloid the registration pins 
driven through it. Then the celluloid should be laid on the 
second colour print, the sketched-in outlines made to coincide 
and the pins driven through the print. The third print is 
treated in the same way. 

Another simple method was suggested by Bohm, as shown 
in Fig. 9, in which a is a sheet of plate glass on which is 





Fig. 9 


placed a sheet of fluffless, smooth blotting paper, then on this 
the freshly inked bromoil 6, and then a sheet of smooth, hard 
drawing paper c. The latter is preferably fastened at one 
end to the glass plate so as to prevent it shifting. As a roller 
a knitting needle of one-eighth inch diameter is used, which 
can be seen as the little round circle between the boards. 
Pressure is obtained by means of the top board. The transfer 
can be examined after it has been rolled, and if unsatisfactory 
can be rolled again in the same direction. For prints larger 
than 5 x 7 it is preferable to use a rather more elaborate 
arrangement, shown in Fig. 10. This acts well up to 16 x 20. 





Fig. 10 


On each of its longer sides a U-shaped iron strip is fastened 
by two or three screws; the holes must be about two-fifths 


OIL AND BROMOIL Jit 


of an inch long, as can be seen on the side shown, so that the 
screws may work up and down. On the lower surfaces of the 
U-iron are fastened some pieces of soft rubber. Real soft 
rubber, such as used for erasing, should be used, and the 
number of pieces will depend on the softness. On the base- 
board is placed first a sheet of linoleum or soft blotting paper, 
then the fluffless sheet, then the bromoil and the transfer 
paper. It is also advisable to cover the transfer paper with a 
sheet of smooth firm drawing paper, and the layers under 
the bromoil should not be too soft or it may wrinkle up. 
The pressure or top board is of the same thickness as the 
bottom one. It is important that this board ride smoothly 
between the ways, and the handles shown on top facilitate 
pressing it to and fro. The knitting needle is used as in the 
smaller arrangement. Increased pressure can be obtained by 
using more papers under the bromoil. It is very important 
that the top piece does not warp and the cross pieces, which 
should be screwed to it, with the heads of the screws well 
sunk in, will prevent this. If necessary the iron ways may be 
greased to make the board move more freely. 

The bromide print for transfer must be very clean and free 
from fog. Soft ink should be used, and, therefore, the relief 
must be kept rather high. The arrangement of the transfer 
block, ready for passage through a roller press, should be as 
follows: two or four thin cards should be used and over 
these a sheet of thin smooth linoleum, then a sheet of thick 
blotting paper. On this should be placed the transfer paper, 
and the position of the bromoil having been previously 
marked by pencil lines at two opposite corners, the inked 
bromoil should be placed in position and then the same 
arrangement of blotting paper, linoleum and cards placed on 
top, as used under the paper. Great care must be taken that 
there is no sliding action when putting the bromoil in posi- 


312 PHOTOGRAPHIC FACTS AND FORMULAS 


tion, otherwise a smear will be caused. At first very light 
pressure should be used and with each passage of the block 
through the machine it should be increased. The transfer 
can easily be examined by removing the top pack, lifting one 
corner of the bromoil, while holding the main part down with 
a stiff card or straight edge, and the rolling continued if the 
transfer is not enough. If a second pull is desired it is advis- 
able to free the bromoil from any trace of the ink by swab- 
bing with a solvent, such as carbon tetrachloride. It must be 
again immersed in water before inking up again. The num- 
ber of pulls possible from one bromoil varies with the hard- 
ness of the gelatine film and may be from five to twenty-five. 

ANOTHER BroMoIL TRANSFER Process.—A direct print 
or enlargement should be developed with a non-tanning devel- 
oper, such as amidol, fixed in a plain hypo bath, well washed, 
and then bleached in the following: 


Potassium bromide 10 ¢ 77 gr. 
Cupric sulphate l5¢ 115 gr. 
Potassium bichromate 5¢ 38.5 gr. 
Water 1000 ccm 16 oz. 


Dissolve in the above order, and add sufficient hydrochloric 
acid to form a clear solution. After complete bleaching, 
wash well, and treat with a 1 per cent sulphuric acid bath to 
remove any yellow colour. Again wash, fix in a 20 per cent 
solution of hypo, and wash. Immerse the print for 10 min- 
utes in: | 

Glycerine 333 ccm Sin 

Water 667 ccm 10 oz. 
Place face up on a clean glass plate, and roll down with a 
roller squeegee. Now fasten the edges down to the glass with 
strips of gummed paper. Ink up with a roller with a greasy 
ink, litho or collotype. If the paper is too much hardened, 
the ink will take on the parts which should be white; then it 


OIL AND BROMOIL oS 


should be immersed again in the glycerine solution at a tem- 
perature of 30° C. (86° F.), or until the ground shows a 
distinct relief ; then stick down again to the glass and ink up. 
It is stated that at least 100 pulls can be taken from this, and, 
of course, in any colour. The process is also applicable to 
three-colour work. 


Miscellaneous Printing Processes 


THE PowpbeEr Process.—This process is based on the fact 
that colloids lose their tackiness on exposure to light in 
contact with a bichromate. It is rarely used for paper prints, 
and its chief application has been for the preparation of re- 
versed and duplicate negatives for photo-mechanical work, 
or for making ceramic enamels. For the latter process the 
image was produced on collodionised glass to facilitate strip- 
ping, and the image transferred to the enamel plaques. 

The following are typical formule: 


Dextrine 40 ¢ 307 gr. 
White sugar 50 g 384 gr. 
Ammonium bichromate 20 g 154 gr. 
Water 1000 ccm 16 oz. 
Glycerine 20 to 80 drops 10 to 40 drops 
Or: 
Gum arabic 20 g 154 gr. 
White sugar 25 ¢ 192 gr. 
Ammonium bichromate 20 ¢g 154 gr. 
Alcohol 50 ccm 34, OZ. 
Water 1000 ccm 16 oz. 


The alcohol should be added after all the other ingredients 
are dissolved. Or: 


Dextrine 48 ¢ 368 gr. 

Grape sugar 48 g 368 gr. 

Potassium bichromate 48 ¢ 368 gr. 

Water 1000 ccm 16 oz. 
Or (Miethe) : 

Gelatine 5.8¢ 44.5 er. 

Rock sugar candy 194¢ 302z., 177 gr. 


314 


MISCELLANEOUS PRINTING PROCESSES 315 


Potassium bichromate 58 g 445 er. 
Water 1000 ccm 16 oz. 
Soak the gelatine and the candy in the water for 30 minutes, 

dissolve by heat, and add the bichromate, Or (Vogel) : 


A. Gum arabic 160 g 1 oz. 
Sugar 400 g 214 02. 
Honey 80 g 4 oz. 
Water 400 g 24 oz. 

‘ Alcohol 60 ccm 900 min. 


Use warm water to dissolve the gum, sugar, and honey, and 
then add the alcohol; to this should be added a few drops of 
glycerine in dry weather. 

B. Ammonium bichromate, 10% sol. 
For use mix 1 part A, 2 parts B, and 3 parts water, heat to 
50° C. (122° F.), and filter twice. 

Plate glass should be flowed with one of the above solu- 
tions, the excess drained off, the plate dried in a level position 
at 63° C. (145° F.), and exposed while still warm. As the 
powder only adheres to the unexposed parts, a transparency 
must be used and not a negative, if a positive is required. In 
bright sunlight the exposure will be from 1 to 2 minutes, or 
until the image is faintly visible. The plate should then be 
again warmed, until hotter than the room in which the work 
is carried out, and placed on a sheet of white paper. A fine 
powder, such as graphite, sifted on to the surface from a fine 
muslin bag, is gently brushed over the whole surface with a 
very soft brush. As the unexposed parts absorb moisture, 
the powder will adhere, and gently breathing on the film will 
cause it to adhere more quickly. As soon as the image is 
intense enough, the excess powder should be brushed off, the 
plate coated with 2 per cent plain collodion, and, when this is 
set, immersed in a 5 per cent solution of alum until free from 


316 PHOTOGRAPHIC FACTS AND FORMULAS 


yellow stain, then rinsed and dried. Instead of using the 
collodion, the plate may be treated with: 


Sulphuric acid 75 ccm Voz: 
Water 300 ccm 4 oz. 
Methyl alcohol 600 ccm 8 oz. 


until all yellow colour disappears, then gently washed with 
water, and dried. The image is very tender and very liable 
to damage. If it is not to be stripped from the glass, it is 
advisable to give the glass a preliminary coating of a 2 per 
cent solution of sodium silicate. 

THE PEPPER DUSTING-ON PROCESS.— 

A. White pepper 400 g 8 oz. 
Benzole 1000 ccm 20 oz. 
Allow to stand for 24 hours with frequent shaking; then 

filter. 

B. Gum dammar 50 g 1 oz. 

Benzole 1000 ccm 20 oz. 

C. Solution of rubber in benzole; bicycle tire cement will do. 
For use mix 10 parts A, 1 part B, 1 part C, filter, coat any 
surface, and dry in the dark. Expose under a transparency 
for a few minutes in the sun, dust over with any dry litho or 
other colour, or bronze. Finally brush clean with a soft 
brush. 

NEGROGRAPHIC Process (Itterheim).—Smooth well-sized 
paper should be rather thickly coated with: 
Gum arabic 250 ¢ 4 oz. 
Water 1000 ccm 16 oz. 
The gum should be in clear small lumps and preferably sus- 
pended in a fine muslin bag in the water, which may be warm. 
,When all has dissolved, add: 
Potassium bichromate 50 g 384 gr. 
When this has dissolved, add: 
Alcohol 10 ccm 77 min. 


MISCELLANEOUS PRINTING PROCESSES 317 


The paper should be hung up to dry. The exposure, under a 
line drawing, is from 5 to 10 minutes in diffused light, or 
until the image is distinctly visible. Immerse in water, not 
too cold, until the lines of the drawing show a distinct relief. 
It should then be surface dried with a soft pad of cloth, and 
hung up to dry. Then coat with: 


Shellac 50 g 384 gr. 
Lampblack 150 g 24 02. 
Alcohol 1000 ccm 16 oz. 


The shellac should be dissolved first, filtered, and then the 
lampblack worked in. A flat brush or soft pad should be 
used for applying this to the print, which, after complete 
coating of the surface, should be immersed in a 2 to 3 per 
cent solution of sulphuric or hydrochloric acid, until on gentle 
application of a soft brush or pad the black pigment comes 
away from the ground leaving the lines of a good intense 
black. 

ANTHRACOTYPE (Sobacchi)—Well-sized paper should be 
coated with a gelatine solution: 

Gelatine 33 2 258 gr. 
Water 1000 ccm 16 oz. 
Allow to soak for 15 minutes, melt at 40° to 50° C. (104° to 
122° F.), and filter. Immerse the paper for 10 minutes in 
water, then place face up on a sheet of glass, and lightly 
squeegee into contact, or a soft linen pad may be used. The 
edges of the paper should be turned up to the height of about 
lcm. (3% in.) so as to form a dish, and the gelatine solution 
poured in, allowing 620 ccm per qm (2 oz. per sq. ft.). As 
soon as the gelatine has set, hang up to dry. This paper will 
keep indefinitely. To sensitise immerse for 2 minutes in a 
4 per cent solution of potassium bichromate, and dry in the 
dark; this paper will keep for about a week. Expose under a 
drawing from 12 to 60 seconds in sunlight until the image is 


318 PHOTOGRAPHIC FACTS AND FORMULAS 


faintly visible. Immerse in running or frequently changed 
water, until all trace of yellow disappears. Then immerse in 
water at 28° to 30° C. (82° to 86° F.) for one minute, imme- 
diately place face up on a sheet of glass or flat board, and 
remove surface moisture with fluffless blotters or a soft linen 
pad. Finely powdered lampblack or other powder should be 
dusted over the surface through fine muslin; a small sieve 
can easily be made from a lidless box. Then a soft round 
badger brush should be used with circular strokes to distribute 
the powder, which should only adhere to the unexposed parts. 
When the image is fully visible, the print should be exposed 
to the sun or in a moderately warm oven, not over 60° C. 
(140° F.), until completely dry. At this temperature the 
gelatine softens, and the powder sinks slightly into it. When 
thoroughly dry, immerse in cold water until it lies quite flat, 
then place face up on a board, and rub the surface gently 
with a soft pad until the ground is white. Should the powder 
not adhere sufficiently to the lines, the powdering operation 
may be repeated as often as necessary, a warm water bath 
being used each time, and, if necessary, the temperature raised 
a few degrees to thoroughly soften the gelatine. The print 
then only requires drying. 

THE ANILINE Process (Willis) —The basis of this pro- 
cess is the reduction of a bichromate by the action of light 
and the formation of an aniline colour on the exposed salt 
by the vapour of aniline or like compound. 

Well-sized paper should be floated on (Reynolds) : 

Potassium bichromate, 


sat. sol. 1000 ccm 16 oz. 
Sulphuric acid 45 ccm 345 min. 

Or (Dawson) : 
Ammonium bichromate 104 ¢ 798 gr. 


Glacial phosphoric acid 42 to 126g 323 to 968 gr. 


MISCELLANEOUS PRINTING PROCESSES 319 


Water 1000 ccm 
Or (Vogel) : 

Potassium bichromate oy 

Phosphoric acid, sp. gr. 1.124 500 ccm 

Water 500 ccm 
Or (Weissenberger) : 

Potassium bichromate 100 ¢ 

Sulphuric acid 133 ccm 

Water 1000 ccm 


16 oz. 


38.5 gr. 
8 oz. 
8 oz. 


770 gr. 
1020 min. 
16 oz. 


The sulphuric acid in this formula may be replaced by 
122 ccm (936 min.) phosphoric acid, sp. gr. 1.117. 


Or (Weissenberger) : 


Potassium bichromate 66.6 g 
Potassium bisulphate 300 g 
Manganese sulphate 26.6 
Water 1000 ccm 
Or (Weissenberger ) : 
Potassium bichromate 75g 
Sodium acid phosphate 200 g 
Magnesium chloride 75 2 
Water 1000 ccm 


This last is said to be the best formula. 


SlZ or. 
2304 gr. 
205 gr. 
16 oz. 


576 gr. 
1536 ger. 
576 gr. 
16 oz. 


Paper, which must be free from wood pulp, should be 
floated on one of the above for from 1 to 2 minutes and 
rapidly dried. Exposure in diffused light will vary from 10 
to 60 minutes, according to the thickness of the paper on 
which the drawing is made. In sunlight the exposure will 
be about one-third of the time. Development is best effected 
by laying the paper at the bottom of a box to the lid of which 
is pinned a sheet of stout blotting paper moistened or sprayed 


with: 
Commercial aniline 500 ccm 
Benzole 500 ccm 


8 02. 
8 oz. 


320 PHOTOGRAPHIC FACTS AND FORMULAS 


The image should appear in a few minutes and will be a dirty 
blackish-green. The colour is somewhat dependent on the 
duration of the aniline fuming; the shorter this is the bluer 
the final print; the longer the time the more blue-black the 
colour. The fuming time is dependent on the exposure. 
When the image is intense enough, immerse the paper in 
water, running or frequently changed, until the whites are 
pure. If the whites will not clear, immerse the print in a 
1 per cent solution of sulphuric or 3 per cent hydrochloric 
acid; then wash, and the green will be formed, which can be 
converted into blue by treatment with a 1 per cent solution of 
ammonia. 

ANILINE BLACK OR ENDEMANN’S Process.—This is also 
sometimes called vanadium printing. Aniline black is formed 
by the action of a vanadium salt. The sensitiser is: 


Salt 3l¢g 238 gr. 
Potassium bichromate 31g 238 er. 
Sodium vanadate 0.043 ¢ 0.33 gr. 
Sulphuric acid 65 ccm 500 min. 
Water 1000 ccm 16 oz. 


Well-sized paper, preferably sized with a 2 per cent solution 
of gelatine, is floated on the above or the solution may be 
applied with a brush and dried. Exposure should be about 
7 minutes in diffused light, and the print should then be 
exposed to the vapour of a 2 per cent solution of aniline in 
warm water, which should be heated in a dish. The image 
will appear in a brown colour and the paper should then be 
exposed in a very damp room or box at 24° to 30° C. (75° 
to 86° F.) for about 2 hours, or until quite black. Finally, it 
should be washed with dilute ammonia, 1:6, and dried. 
FEERTYPE, PRIMULINE AND DIAZOTYPE PROCESSES.— 
These processes are but rarely used and are more applicable 
to fabrics than to paper. They are based on the light-sensi- 


fieereANEOUS PRINTING PROCESSES 321 


tiveness of complex organic compounds, which under the 
action of light form coloured dye images. Feer suggested the 


following: 

A. Sodium toluoldisazosulphonate 25 g 192 gr. 
Beta-naphthol 25 ¢ 192 gr. 
Caustic soda 8g 61 gr. 
Water 1000 ccm 16 oz. 

Gives scarlet red images. 

B. Sodium ditolyltetrazosulphonate 25 ¢ 192 er. 
Metaphenylendiamine 20 g 154 er. 
Water 1000 ccm 16 oz. 

Gives brown images. 

C. Sodium ditolyltetrazosulphonate 25 g 192 ger. 
Resorcine Lae 169 er. 
Caustic soda l6g 122 gr. 
Water 1000 ccm 16 oz. 

Gives orange images. 

D. Sodium ditolyltetrazosulphonate 30 g 230 gr. 
Resorcine 20 g 154 er. 
Caustic soda lage Lider: 
Water 1000 ccm 16 oz. 

E. Sodium ditolyltetrazosulphonate 30 g 230 gr. 
Alpha-naphthol 20g 192 gr. 
Caustic soda 7g 54 gr. 
Water 1000 ccm 16 oz. 

F. Sodium ditolyltetrazosulphonate 30 ¢ 230 ger. 
Paraphenylendiamine 20 g 154 ger. 
Water 1000 ccm 16 oz. 


A, B, C can be used alone; D and E mixed in equal volumes 
for violet tones; or E and F in equal volumes for blue tones. 

After exposure, which is about 5 minutes in sunlight, the 
prints should be washed in water acidulated with hydro- 
chloric acid. 


322 PHOTOGRAPHIC FACTS AND FORMULAS 


The primuline process was patented by Green, Cross and 
Bevan. The process is as follows: 
Primuline 33 g 253 gr. 
Hot water 1000 ccm 16 oz. 
Filter and immerse the fabric in the warm solution for about 
10 minutes, wash thoroughly, and immerse for 5 minutes in: 


Sodium nitrite (not nitrate) 6.6¢ 51 gr. 
Hydrochloric acid 15 ccm 115 min. 
Water 1000 ccm 16 oz. 


Dry in the dark. Exposure must be made under a positive, 
if a positive print is required. Then the print is thoroughly 
washed, and treated with one of the following developers. 


For red tones: 


Beta-naphthol 10g 77 gr. 

Caustic soda I3 ¢g 100 gr. 

Water 1000 ccm 16 oz. 
For orange tones: 

Resorcine Prog 19 gr. 

Caustic soda ll¢g 84 er. 

Water 1000 ccm 16 oz. 
For purple: 

Alpha-naphthylamine 20 g 154 gr. 

Hydrochloric acid 3 ccm 23 min. 

Water 1000 ccm 16 oz. 
For blacks: 

Eikonogen l3 ¢g 100 gr. 

Water 1000 ccm 16 oz. 
For brown: 

Pyrogallol 12¢ 92 gr. 

Water 1000 ccm 16 oz. 


The prints must be well washed after development, and if 
on fabric ironed before quite dry. Unfortunately, it is almost 
impossible to obtain pure whites by this process. 


MISCELLANEOUS PRINTING PROCESSES 323 


Andresen suggested the following process: 


Benzidine Za s 177 gr. 

Water 1000 ccm 16 oz. 
Boil until dissolved, and add: 

Sulphuric acid 37.5 ccm 288 min. 

Water 37 com 288 min. 


Allow the mixture to cool; then with the aid of ice reduce 
the temperature to 5° to 10° C. (41° to 50° F.), and a copious 
precipitate should be formed. Add slowly: 


Sodium nitrite (not nitrate) 18 ¢ 138 er. 

Water 50 ccm 34 OZ. 
Stir until a clear solution is obtained, and pour into: 

Alcohol 5000 ccm 80 oz. 


The diazobenzidine will be precipitated. Filter and wash 
with alcohol two or three times, and dissolve in: 

Water 1000 ccm 16 oz. 
During solution the water must be kept cooled down to 5° C. 
(41° F.). This precipitate must not be allowed to dry, as it 
is very explosive. Keep the solution cool, and float paper 
on the surface, or immerse fabrics completely. Dry in the 
dark, and expose under a positive. The developer may be a 
2 per cent solution of amido-naphthol-sulphonic acid-5 or 
the corresponding -9 compound with 2 per cent caustic soda. 

Andresen also patented the following process: 


Water 150 ccm 5 oz. 
Heat in a porcelain dish to boiling, and add: 

Beta-naphthylamine 14.3 ¢g 220 er. 
Add slowly: ) 


Hydrochloric acid, sp. gr.1.19 10 ccm 152 min. 

Stir until dissolved, and add with constant stirring: 
Hydrochloric acid 40 ccm 617 min. 
Cool the thick paste with ice to 5° C. (41° F.), preferably by 

adding the ice to the liquid, and add with constant stirring : 


324 PHOTOGRAPHIC FACTS AND FORMULAS 


Sodium nitrite 10 g 154 gr. 
Filter into an ice-cold dish. Paper should be floated on the 
cold solution, or fabric immersed, wrung out, and dried in 
the dark. Exposure under a negative will be from 8 to 12 
minutes in diffused light, and the image shows in a brown 
colour on the yellow ground. Development should be effected 
with a 10 per cent solution of fused sodium acetate, which 
gives brownish-red tones. If alpha-naphthylamine be used, 
brownish-grey tones are obtained. Better colours are ob- 
tained by adding a little of the sensitising solution to the 
developers. The prints should be subsequently washed, and 
dried. 

Schoen patented the use of diazotised ortho-amido-salicylic 
acid and its compounds for obtaining coloured prints on paper 
and fabrics, red tones being given, which can be altered by 
treatment with various compounds, such as ferric chloride, 
lead acetate, cobalt nitrate, lime or baryta water. 


Mountants 


DEXTRINE—An excellent preparation, when properly 
made, which keeps well and adheres firmly : 


White dextrine 1000 g 1 Ib. 
Alum 40 g 280 er. 
Sugar 156 g 2Y4 oz. 
Water 1200 ccm 19% oz. 
Phenol (carbolic acid) 3 ccm 22 min. 


Mix the dextrine with the water, boil for 5 minutes, add the 
sugar and the alum; stir until dissolved, allow to cool slightly, 
add the phenol, and cast into wide-mouthed bottles. Inferior 
dextrine gives a coloured paste; the alum is preferably left 
out, as it may subsequently cause fading of the prints. If 
the bottles filled with the paste are cooled for several days in 
a refrigerator, the paste sets to a white firm mass. A simpler 
formula is: 


White dextrine 1000 g 1 Ib. 
Water 625 ccm 10 oz. 
Wintergreen or clove oil 10 ccm 60 drops 
On: 
White dextrine 1000 g 1 Ib. 
Water 1500 ccm 24 oz. 
Oil of wintergreen 2 ccm 12 min. 
Oil of cloves 2 ccm 12 min. 


Place the water in a vessel standing in a water bath, and keep 
the temperature at 71° C. (160° F.); stir in the dextrine 
slowly, and, when it has all dissolved, add the oils. Set ina 
cool place for several days, when it will congeal to a firm 
white paste. 

DEXTRINE AND GumM.—A very adhesive paste: 


325 


326 PHOTOGRAPHIC FACTS AND FORMULAS 


Picked white gum arabic 62.5 g YZ oz. 
Dextrine 290 g 2% oz. 
Ammonia 1 ccm 4 drops 
Phenol (carbolic acid) 15 ccm 60 min. 
Water 1000 ccm 8 oz. 


Powder the gum, and mix with the dextrine into a smooth 
paste with one-fourth of the water; then add the rest of the 
water, and boil for 10 minutes. Strain through linen, and 
add the phenol and ammonia when cold. 

GELATINE.—This must be used hot. A piece of ground 
glass should be dipped in hot water, drained, and the mount- 
ant brushed over. The print is then laid face up on the 
pasted surface, rubbed gently into contact with a piece of 
paper, and is then pressed on to its mount: 


Soft gelatine 187.5 ¢ 3 oz. 
Water 750 ccm 12% oz. 


Soak the gelatine in the water, melt in a water bath, and add 
slowly with constant stirring : 
Methyl alcohol 225 ccm 4 oz. 
Glycerine 25 ccm 96 min. 
It is preferable to omit the glycerine, and use corn or sugar 
syrup, or add sugar in the same proportion. 
LiguiIp GELATINE.— 


Gelatine 100 g Loz; 
Water 600 ccm 6 oz. 
Chloral hydrate 100 g 1 oz. 


Soak the gelatine in the water, melt by the aid of heat, add the 

chloral, heat for 15 minutes, and then add sodium carbonate 

until the mixture is neutral to litmus paper. 
STARCH-GELATINE.— 


A. Bermuda arrowroot 200 g 8 oz. 
Water 100 ccm 4 oz. 
B. Soft gelatine 20 g 360 gr. 


Water 1600 ccm 64 oz. 


MOUNTANTS af 


Soak the gelatine in the water and melt with heat. Rub the 
arrowroot into a cream with the water, add to the gelatine 
solution, and boil 10 minutes, with constant stirring. Allow 
to cool, add add: 

Methyl alcohol 125 ccm 5 oz. 


Phenol 1.3 ccm 25 min. 
STARCH Paste.—This will not keep longer than a week: 

Pure starch 100 g 1 oz. 

Benzoic acid rae 6 gr. 

(Or salicylic acid) 2.5¢ 1S:er; 

Water 1200 ccm 12 oz., 


Rub the starch and the acids into a very stiff paste with a 
little water ; it should be so stiff that it is difficult to stir. Add 
the rest of the water boiling, and stir well, when a clear 
smooth paste should be formed. If it is not quite clear, boil 
for a few minutes. Allow to get quite cold, and take off 
the skin that forms on the surface. Somewhat increased 
keeping power is obtained by the addition of formaldehyde, 
1.2ccm (6 min.), which should be added when the paste is 
cold. Wheat or preferably rice starch should be used. 
Dry Mountine (Briand ).— 


Shellac, white or pale yellow 3002 Bes 

Denatured alcohol 333 g 5Y4 oz. 
Dissolve. 

Gum elemi 30 g 230 gr. 

Denatured alcohol Sosccny 5Y4 oz. 
Dissolve: 

Canada balsam 50 g 384 gr. 

Denatured alcohol 334 ccm BOs 


Dissolve, and mix the three solutions. Paint on tissue paper, 
and allow to dry for 5 minutes, then paint the other side and 
dry. Place between mount and print, and pass a hot iron 
over the two. 


Stereoscopic Work 


SEPARATION OF THE LENSES.—This should be equal to the 
interpupillary distance of the eyes, which is approximately 
65mm (2 9/16in.), but 76mm (3in.) is usually adopted 
for normal work. When taking near objects, the centers of 
the lenses must be brought nearer to one another, and the 
rule for finding how much is: if the additional extension of 
the camera beyond the infinity mark or focus is equal to the 
focal length multiplied by 17, then the separation must be 
reduced by an amount equal to the maximum separation 
multiplied by 1— (r+ 1), in which r is the ratio of image 
to object. Example, the image is to be made one-quarter 
the natural size, then 1 + (r + 1) = 1/5, so that the separa- 
tion must be 3 — 3/5 inches. 

MountTING Prints.—To secure correct conditions of con- 
vergency, each print must be seen under the same angle of 
view as that at which it was produced, and the two prints 
must be mounted in accord with the following rule: 

Let P = separation of any pair of corresponding points on 
prints 

N = separation of same points on negatives 

FE = separation of eyes (average is 64 mm) 

L =separation of camera lenses. 
A non-prismatic stereoscope being used: 
1. If image points represent infinitely distant objects, 

Make ? == i) 
2. If only near objects are shown, and an ordinary single 
plate double lens stereo camera has been used, 
Make P=E+L—WN 

3. If a single camera is used for two separate exposures, or 


328 


PEER EOSCOPIC WORK 329 


if two separate similar cameras are used together, measure N 
with negatives placed edge to edge, and in the same relative 
positions that they occupied during exposure; then 

Make P = E—WN -+ length of one plate. 
If a prismatic stereoscope, fitted with properly centred half 
lenses, is used, add the width of one prism to above values 
Lar: 

Frequently, if the prints are cut apart, errors may arise, 
and they may be wrongly mounted. To avoid this, place the 
prints face down on the table, with the top away from you, 
and across the central dividing line draw a faint pencil line, 
about one inch long. Then cut the prints in two, and, after 
trimming, mount them so the pencil lines fall on the outside 
margins of the prints. 

In order that the picture shall be viewed as through a dark 
frame, which is the most effective way, trim the prints as 
follows: the prints should be 214 inches wide, but mounted 
with an eighth of an inch between them, and trimmed so 
that there is one-eighth of an inch more subject shown on 
the right-hand side of the left-eye print than on the right 
of the right-eye print, and one-eighth of an inch more subject 
shown on the left of the right-eye print than on the left of 
the left-eye print. 


Lantern Slides 


STANDARD SizEs.—British, 34%4 x 3% in.; American, 4 x 
31%4 in. Maximum size of picture 3 x 3 in. in both cases. 

SPoTTinc.—The standard spotting in Britain and the Col- 
onies is with two round spots of colour distinct from that 
used for the binding, placed at the top of the picture, when 
viewed as it appears in nature. These spots go downward, 
and next the condenser when projecting. The American 
standard method is to spot with one “thumb-spot’” at the 
bottom left-hand corner of the picture, as viewed in its 
proper direction. This spot is covered by the thumb of the 
right hand, when the lantern is fed from the right hand side, 
and is at the upper right-hand corner, next to the condenser, 
during projection. 


ADHESIVE FOR BINDING STRIPS.— 


Sugar candy 100 g 240 er. 

Water 100 ccm 4 oz. 
Dissolve by heat, and add to: 

Fish glue 400 ccm 202 


Brush on thin needle (black) paper, dry, and cut into strips. 
The strips may better be purchased when only small quantities 
are needed. 

LANTERN SLIDE D1acRrAMs.—Draw with a hard pencil on 
fine ground glass, and varnish with a strong solution of gum 
dammar in benzole. Or coat plain glass with: 


Sandarac 16.5 ¢ 128 gr. 
Mastic 16.5¢ 128 gr. 
Ether 800 ccm 13 oz. 
Benzole 165 ccm 21% oz. 


330 


LANTERN SLIDES 331 


This gives a fine grain and takes the pencil well. To make 
it again transparent, coat with: 


Sandarac 30 g 240 er. 
Mastic 30 g 240 er. 
Ether 1000 ccm 16 oz. 
DIAGRAM LANTERN SLIDES.— 
Canada balsam 4 parts 
Pure turpentine 8 parts 
Liquid siccative 1 to 2 parts 


Mix thoroughly, and add as much lampblack as will give it 
the consistency of an ointment. Coat glass evenly with a 
badger hair softener. Or: 


Syrian asphalt 50 parts 
Yellow Venice turpentine 10 to 12 parts 
Linseed oil or varnish 15 parts 
Pure turpentine 15 parts 


Melt the asphalt and Venice turpentine in the turpentine by 
heat, and add the linseed oil with continual stirring. Add 
enough lampblack to make it as thick as ointment. Well- 
cleaned glass should be coated with this until opaque, and 
allowed to dry; then rubbed over with a little lampblack 
rubbed up with gum water. This will be repelled at first but 
with continual working will take. A good-sized darning 
needle mounted in a wooden handle may be used as the 
graving tool. Broad surfaces may be scraped out with a 
sharp knife. The above give white lines on a black ground. 
DEVELOPMENT.—Numerous formulas have been proposed 
for lantern slide plates. A few American manufacturers’ 
formulas are given, and are adaptable to other brands. 
Hammer Transparency Plates.— 
Metol 2g 30 gr. 
Sodium sulphite 62.5 g 2 oz. 
Hydrochinon 15.6 ¢ Y oz. 


332 PHOTOGRAPHIC FACTS AND FORMULAS 


Sodium carbonate 78g 2 02. 
Potassium bromide 2g 30 gr. 
Citric acid 2g 30 gr. 
Water 1000 ccm 32 02. 
Extreme Density Developer. Hammer Plates.— 
Hydrochinon Zoe V4 oz. 
Sodium sulphite 100 g PAG 2 
Sodium carbonate 150 g 3 Oz. 
Potassium bromide 6.25 g Y% oz. 
Water 1000 ccm 20 oz. 


Use full strength at 65° F. 
Seed Lantern, Black Tone Transparency Plates. — 


A. Elon (metol) 4¢ 30 gr. 
Hydrochinon 4¢ 30 gr. 
Sodium sulphite, dry I7 ¢g 130 gr. 
Water 1000 cem 16 oz. 

B. Potassium bromide 2¢g ince 
Sodium carbonate, dry 13 g 100 gr. 
Water 1000 ccm 16 oz. 


For use mix in equal volumes. Temperature about 70° F. 
Seed Hydrochinon Developer for Warm Tones.— 


A. Hydrochinon 6.5 g 50 gr. 
Sodium sulphite, dry 2.6 ¢g 20 gr. 
Potassium bromide 0.65 g Ser 
Citric acid 0.65 g 5 gr. 
Water 1000 ccm 16 oz. 

B. Sodium carbonate, dry 31.25 g Y, oz. 
Caustic soda 3.9 ¢ 30 gr. 
Water 1000 ccm 16 oz. 


For use mix in equal volumes. For still warmer tones use 
more B. 
Cramer's Hydrochinon-Pyrocatechin Developer.— 
A. Sodium sulphite, dry 180 g 6 oz. 


LANTERN 


Pyrocatechin 
Hydrochinon 
Potassium bromide 
Water 

B. Caustic potash 
Water 

Mix in equal volumes. 


SLIDES 


960 ccm 
l6g 
960 ccm 


240 er. 
240 er. 
120 gr. 
32 oz. 
240 gr. 
32 oz. 


333 


Enlarging 


TABLE FOR ENLARGING AND REDUCING.— 


A 23 4 6 
B. 3—1% 4-11/3 5—1% 7—11/6 8—11/7 9—-1% 
A. 9 10 11 12 


B. 10—11/9 11—11/10 12—11/11 13—11/12 
To find the number of linear times of enlargement or reduc- 
tion, divide the longer side of the enlargement by the longer 
side of the negative. Then find this number in the top row A, 
and multiply the lens focus by the numbers in the lower row 
B. The greater distance is that between the lens and sensitive 
paper, and the lesser that between the lens and negative. 
Example: To enlarge 5 x 4 to 20x 16. As 20-+5 =—4, if 
a 6-inch lens be used, the distances will be respectively 
6X 5=30and6 X 14% =—7%Y in. For reducing, the relative 
positions of the sensitive surface and negative or copy are 
reversed, thus to reduce a 20 x 16 four times with a 6-inch 
lens, the latter will be 30 inches from the subject and 7% 
inches from the plate. 


334 


ENLARGING S30 


RELATIVE ExposurES WHEN ENLARGING (WITHOUT A 
ConDENSER) (B. J. Almanac ).— 


mee tees: epee + — A 










































































sg he Time of enlargement for which exposure is known. 
Z8a g si ey 
ae te 2 2b 3 | 3h 4 56 8 107 12, 
vo wee eee st | Oe eee ee ola | oo 
13 | 13] 1 Tee ett ert |e) | te | ae ts 
ae eet 1X1 1 Pele ae lade She ord ae 
Beemer oe te ie Pee RP oe SL tl 4a oe lS 
3 | 4 | 24] 16] 14] 1 Eres hela Sat okey ct eer 
34}5 | 34] 24 { 1211411 Pebaecl le Ri aey cee el os 
See ie S12} 1k} 1h)4 eae ae Se ee 
5 | 9 16 | A'S | Qi} 12] 14)1 aa eae a ee 2 
oases) 4. | 3 18h} 25)12 | 4) £13 b 4 
mepeeo ts 19 17 15 |4 | 34) 2) 12-51 $| 4 
fee ie ais 410 17 | 6 15 13h | 23) 14 F : 
torte ie? 419, 1411 | 84.7 1 4213¢ 12 118 11 

















To use this table find in the top horizontal line the number of times of en- 
largement for which exposure is known. Under this number the relative time 
of exposure for different degrees of enlargement will be found opposite the 
new times of enlargement in first vertical column. 


RELATIVE EXPOSURES WHEN CopyYING or Repucine (B. J. 
Almanac ).— 
























































Besa Scale of reduction for which exposure is known. - 

2438 

ee a ae ee ee 
1 Pry ie | th] le | 2k | 2k | 3 |S | 3 ft Sh Sk Of 33 
3 S14 | iy 14] 1212 | 2 | 22] 2k) 2413 13 
_# Pio eee | AR Ue 1 2 12) 2h) 23) 2h] 2h 
‘4 Petteert eal jit lel gle 2-12-1242 
$ | i | pepe AS | Id tt Ht | te] 
Pere eee et ee Pt ee 12] 1d pid teh 
NSS TES as We Seis Wie Sieg es We Wee Wee a be or 
TREE GHEEE 
Pee eee bial et bit tt it Vial 
to eeeeetieae lee perge) 2] eR ed pd ete We ag 
to aie id foie Lie |i 
eee tk | Et etl et le 











To use this table find in the top horizontal line the scale of reduction for 
which exposure is known. Under this scale the relative time of exposure for 
different degrees of reduction will be found opposite the new scales of reduc- 
tion marked in first vertical column. 


336 PHOTOGRAPHIC FACTS AND FORMULAS 


SoLAR PRINTING.—Frequently used for making enlarge- 
ments with plain surfaces for working-up with crayon, water 
colour and oils: 


Potassium iodide 16.5 ¢ 125 gr. 
Ammonium bromide 7.3 50 gr. 
Ammonium chloride 2g 16 gr. 
Gelatine Zo 96 gr. 
Albumen 110 ccm 134 oz. 
Water 1000 ccm 16 oz. 


Soak the gelatine in three-fourths of the water for 30 min- 
utes, melt in a water bath, add the salts, cool down to about 
38° C. (100° F.), add the albumen, which should have been 
previously whipped to a froth and allowed to liquefy, and 
add enough water to make up to bulk. Apply to the paper 
with a sponge or Blanchard brush, and dry. Sensitise with: 


Silver nitrate 100 g 14 oz. 
Glacial acetic acid 50 g 3 OZ. 
Water 1000 ccm 16 oz. 


Apply with sponge or brush, and dry. The exposure with a 
good light will be about 60 seconds. The developer is: 


Gallic acid 125 96 gr. 
Lead acetate 22 16 gr. 
Water 1000 ccm 16 oz. 


Add just before use a little of the silver nitrate solution. 
Apply with brush or sponge. Or: 


Milk 1000 ccm 16 oz. 

Glacial acetic acid 38 ccm 288 min. 
Stir well, filter, and add to the filtrate: 

Potassium iodide 14.5 g 112 gr. 

Potassium bromide Se 27 gr. 


Paint over the paper, and dry quickly. To sensitise, float on 
or paint with: 
Silver nitrate 84 g 642 gr. 


ENLARGING a7 


Glacial acetic acid 126 ccm Z.0Z. 
Water 1000 ccm 16 oz. 
Develop with: 
Pyrogallol 6.25 ¢ 48 er. 
Glacial acetic acid 83 ccm 640 min. 
Citric acid 0.13 ¢g 1 gr. 
Water 1000 ccm 16 oz. 
Or coat with: 
Arrowroot 20 ¢ 154 ger. 
Potassium iodide 10g Lf or. 
Salt 30 ¢ 230. 31? 
Citric acid Lge? 8 er. 
Water 1000 ccm 16 oz. 


Heat the mixture until a clear liquid is formed, and float the 
paper, or paint the solution on with brush or sponge. Dry. 
Float the paper for 5 minutes on: 


Silver nitrate 75 ¢g 576 er. 

Citric acid Sig ooer 

Water 1000 ccm Livoz, 
Expose until the outlines appear, and float on: 

Gallic acid 2g 15 gr. 

Glacial acetic acid 10g 77 gr. 

Water 1000 ccm 16 oz. 


When the image is dense enough, float the print on repeated 
changes of water, and fix in a 20 per cent solution of hypo. 
CasEIN PApER.—Dissolve as much fresh casein as possible 
in 100 ccm of strong ammonia, precipitate with dilute hydro- 
chloric acid, press the mass through linen, allow to dry, and 


powder it: 
Casein, as above 300 to 400g 5to6% oz. 
Water 1000 ccm 16 oz. 


Boil until dissolved, and add: 
Boric acid LES 88 gr. 


338 PHOTOGRAPHIC FACTS AND FORMULAS 


Hydrochloric acid 11.5 ccm 88 gr. 
Citric acid 7g 54 gr. 
Water 800 ccm 1234 oz. 


Allow the mixture to cool, remove the skin, press through a 
fine cloth, coat the paper, and dry. This will keep any length 
of time. The paper is salted by floating on: 


Ammonium bromide 20g 154 gr. 
Magnesium iodide 48 g 370 gr. 
Magnesium chloride 8g 61 er. 
Water 1000 ccm 16 oz. 
This should be sensitised on: 
Silver nitrate 100 g 768 gr. 
Glacial acetic acid 40 ccm 307 min. 
Water 1000 ccm 16 oz. 


Small sheets may be floated, and large ones can be painted 
with the solution. Expose while damp until the details are 
visible, and develop with: 


Gallic acid 20 g 154 er. 
Lead acetate 10 ¢ 77 gr. 
Glacial acetic acid 75 ccm 576 min. 
Water 1000 ccm 16 oz. 


After development immerse the print in weak soda solution, 
and fix. 


Flashlights 


MertuHops or Usr.—Flashlights may be divided into two 
classes: A, pure magnesium powder blown through a flame; 
and B, magnesium mixed with some substance, rich in oxy- 
gen, which can be fired with a cap, electric or pyrophoric 
spark, etc. The first named are less used at the present time 
than the second class, and they require no comment, as 
special lamps to burn alcohol, benzolene gas, etc., can be 
obtained commercially. 

Gunpowder was one of the first compounds used for firing 
the second class of flashlights ; but it soon gave place to gun- 
cotton or pyroxyline, the usual proportions being pyroxyline 
1 part, magnesium 2 parts. The cotton should be pulled out 
to a loose long tuft and the magnesium sprinkled over it. 
Strips of thin celluloid may be used in the same way, firing 
being effected by a long taper or match tied to the end of a 
stick. The manufacture of flashlights is exceptionally dan- 
gerous, and should not be undertaken by any but experienced 
chemists. 

M1IxTuRES OF MAGNESIUM WITH NITRATES.—In all cases, 
the weight given should be mixed with 1 part of magnesium 
powder. Thorium nitrate, 0.5; this must be dried at 100° C. 
(212° F.) before mixing. Strontium nitrate, 1.5; must also 
be dried. Potassium nitrate, 1.5. Ammonium nitrate, 2; 
not advisable as the salt is hygroscopic, and the mixed powder 
will not keep well. Sodium nitrate, 3. Cadmium nitrate, 1; 
basic cadmium nitrate must be used, which can be made as 
follows: dissolve 100 g (3% oz.) cadmium nitrate in 100 ccm 
(3% oz.) hot water in a porcelain dish, add a few drops of 
10 per cent solution of caustic soda, until a precipitate is 


a0 


340 PHOTOGRAPHIC FACTS AND FORMULAS 


formed. Evaporate until dry, dry for some time at 105° C. 
(220° F.), and reduce to powder. Lithium carbonate, 1; 
alone with magnesium or mixed with one of the above, gives 
a red light. Potassium permanganate, 1.3; does not explode 
when struck; gives brown smoke and more sparks than others. 
Manganese dioxide, 1; should be very finely powdered. Per- 
fectly safe, burns fairly rapidly with little smoke. 

CHLORATES, PERCHLORATES, ETC.—Potassium chlorate, 2 
or 1; must be powdered. Potassium perchlorate, 2; also in 
powder. Sometimes a mixture of the two is used, as chlorate, 
34, perchlorate, 34. Both the salts must be in fine powder 
before mixing, and should preferably be mixed with a feather 
on a sheet of paper, as strong friction is apt to cause an 
explosion. These compounds cannot be sent through the 
post. Potassium or ammonium persulphate, 2. Potassium 
or ammonium bichromate, 2; burns rather slowly. Chrome 
alum, anhydrous, 1; a perfectly safe mixture. 

FLASH SHEETS.—Flash sheets may be prepared by sus- 
pending magnesium powder in celluloid or pyroxyline solu- 
tion, casting on glass and stripping before quite dry. The 
following mixture has also been proposed: 


Magnesium 1 part 
Potassium chlorate 2 parts 
Celluloid varnish 3 parts 


To be used in the same way. Another method proposed is to 
coat paper with starch paste, rub magnesium powder into it, 
and dry. Thin blotting paper, soaked in solution of potas- 
sium bichromate and dried, is thus pasted and dried. 

FLasH CANDLES.—Slow-burning mixtures can easily be 
made, and the so-called time-light candles are small tubes of 
paper, impregnated either with pyroxyline solution or potas- 
sium nitrate, and filled with a magnesium compound. Or 
the containers may be made of thin aluminium foil, 0.1 to 


PUASHLIGH ES 341 


0.3mm thick (1/25 to % inch). Typical mixtures are as 
follows (Novak) : 

Magnesium 2.5, cerium nitrate 1.75, strontium carbonate 
0.75; burns in 5% seconds. 

Magnesium 2.5, cerium nitrate 1.5, strontium carbonate 1; 
burns in 4.5 seconds. 

Magnesium 2.5, cerium nitrate 1.25, strontium nitrate 1; 
burns in 1.3 seconds. 

Magnesium 2.5, strontium nitrate 1, strontium carbonate 1; 
burns in 1.3 seconds. 

Magnesium 2.5, strontium nitrate 1, strontium carbonate 
1.5; burns in 4.3 seconds. 

Magnesium 2.5, magnesium carbonate 2.5; burns in 11.2 
seconds. 

Anhydrous salts must be used in all cases. 

So-called orthochromatic candles can be prepared by in- 
corporating certain salts, which give coloured lights. For 
red, lithium carbonate 1, with the strontium mixture given 
above. For yellow, sodium nitrate 5. For green, cupric 
sulphate 2, barium nitrate 2. 

SLOW-BURNING PowbErRS.—Slow combustion of flash pow- 
ders is also obtained by an admixture of shellac; for instance, 
1 part of shellac is melted by heat with 9 parts of strontium 
nitrate stirred in, allowed to cool, and powdered. Or mag- 
nesium 6, potassium chlorate 12, antimony sulphide 2; or 
magnesium 2.5, strontium nitrate 5, strontium carbonate 2.5, 
amorphous phosphorus 0.25, have also been recommended ; 
but the fumes are poisonous. Bethge patented the following 
mixtures, of which 2 to 3g burn in 30 seconds: magnesium 
2.5, cerium oxalate 1.5; magnesium 2.5; cerium oxalate 1.5, 
vanadic acid 0.08; magnesium 2.5, cerium oxalate 1; mag- 
nesium 2.5, calcium oxalate 0.75; magnesium 2.5, cerium 
oxalate 0.5, calcium oxalate 0.5; magnesium 2.5, manganese 


342 PHOTOGRAPHIC FACTS AND FORMULAS 


oxide 5; magnesium 2.5, cerium oxalate 0.5, manganese oxide 
0.25. The chromates or tungstates of thorium may also be 
used, and the mixtures keep well and give little smoke, such 
as magnesium 1, thorium chromate 2. Lumiére patented the 
use of the chromates of iron, manganese, chromium, nickel, 
cobalt, aluminium, cerium, lead, copper and antimony, as 
giving little smoke. Boric and silicic acid have also been 
patented when added in equal quantity to the magnesium, and 
these mixtures are non-explosive, give little smoke and almost 
as much light as the permanganate mixtures. 

Aluminium may be used in place of magnesium, but it does 
not give quite so actinic a light. It may also be mixed with 
magnesium. <A _ slow-burning aluminium mixture is alu- 
minium 6, potassium nitrate 6, barium nitrate 6, dextrine 2, 
sulphur 1. The aluminium powder is sometimes greasy and 
clumps together ; in this case, it should be mixed with benzole, 
petroleum ether, gasoline, or as these are dangerous, carbon 
tetrachloride may be used. The mixture should be well 
shaken, the powder allowed to settle, the liquid poured off, 
and the powder allowed to dry. 

AMOUNT OF FLASHLIGHT PowpDER NEEDED.—Orostini 
gives the following table of the quantity of magnesium and 
stop to be used: 

Distance of object Quantity of magnesium in grams 
from light 7, f:9.° folate 
1 meter 0.07 0.01 0.2 0.4 0.8 
2 meters 0.28 0.04 0.8 1.6 es 
3 meters 0.63 0.09 1.8 3.6 7.2 
4 meters 1.21 1.06 3.2 64 128 

MAGNESIUM FOR UNDERGROUND Worxk.—Martel divides 
the subjects into two classes: (1) short distances from 15 
to 20 meters, and (2) long distances from 15 to 60 meters. 
For the shorter distances he recommends three or four strips 


FLASHLIGHTS 343 


of magnesium ribbon, 3mm broad and 0.5 meters long, 
wound into a spiral torch which gives an exposure of from 
1¥4 to 3 minutes; from three to six of these spirals will give 
exposures from 15 to 20 minutes; up to 10 meters one spiral 
is enough; up to 15 meters three or six should be used. 
Placing magnesium powder in 5 g lots and firing with a tuft 
of pyroxyline, one charge will be enough up to 10 meters; 
for greater distances successive charges should be fired. 
Flash powders are not satisfactory; they are dangerous and 
give more smoke. For longer distances blow-through lamps 
should be used, using about 8g up to 60 meters; up to 40 
meters 5g. 

DuRATION OF FLAsH.—Londe states that the duration of 
a flash is dependent on various factors; but, calling the 
unknown ingredients of a powder X, the following table 
gives the duration: 1. X 100, magnesium 150, duration of 
flash, 0.07 seconds; 2. X 100, magnesium 175, duration of 
flash, 0.10 seconds; 3. X 100, magnesium 225, duration of 
flash, 0.11 seconds; 4. X 100, magnesium 250, duration of 
flash, 0.12 seconds. 

Old powder fires more slowly than freshly mixed. The 
weight of the charge plays a part in the duration: 1 g burns 
for 0.03 seconds, 2g for 0.05 seconds, and 3g for 0.07 
seconds. 7 

The particular manner in which the powder is laid also 
affects the flash: 1 g in a heap burns for 0.2 seconds, while 1 g 
spread out burns for 0.4 seconds. 

The method of firing also affects the duration: Electric, 
duration 0.14 seconds; percussion cap, 0.144 seconds; match, 
0.188 seconds; touch paper, 0.280 seconds. 

Any flash longer than 0.12 seconds will show movement 
of the eyes. 


Colour Photography 


THREE-CoLouR FILTERS.—The quantity of dyes is given 
in grams per square meter and grains per 1000 square inches. 
An 8 per cent solution of gelatine should be prepared (see 


Orthochromatics). 
Red filter: 
Rose Bengal 1 253¢ 12.5320; 
Tartrazine 2.0¢ 19.9 gr. 
Green filter: 
Naphthol green 0.4¢ 3.98 gr. 
Patent blue 0.2 ¢g 1.99 er: 
Tartrazine 10¢g 9.95 gr. 
Blue-violet filter : 
Acid rhodamine 0.6 g 5.97 gr. 
Toluidine blue 18¢g 17.91 gr. 


The usual quantity of dyed gelatine is 700 ccm per qm (15 oz., 
435 min., per 1000 sq. in.). 

ADDITIVE Fitters.—These are used for additive projection 
or with the photochromoscope. The gelatine should be pre- 
pared as previously described. 

Blue-violet filter : 
Crystal violet 1.38 g 2.63 gr. 
Methylene blue 0.46 g 0.876 gr. 
A few drops of glacial acetic acid should be used to dissolve 
the above. Allow the same quantity of dyed gelatine to the 
same area. 
Green filter: 


Tartrazine 0.533 5.3 gr. 
Patent blue 0.089 g 0.883 gr. 
Naphthol green 0.178 g 1.76 gr. 


344 


COLOUR PHOTOGRAPHY 345 


The green filter is always difficult to adjust, and it is advis- 
able to make four or five of different depths, increasing the 
quantity of dye by one-fifth each time. 


Red filter : 
Tartrazine 2.03 g 20 Af or. 
Rose Bengal 77s LPS 2 on: 


In order to prevent the double reflection from the back of the 
plain mirrors in the chromoscope, under the red filter should 
be placed a plain glass coated on the back with: 

Patent blue 0.0285 g 0.284 er. 
Under the blue filter, should be placed a plain mirror coated 
with: 


Tartrazine 0.0142 g 0.142 gr. 

Naphthol green 0.023 g Oe or. 

Patent blue 0.0345 ¢ 0.340 gr. 
AUTOCHROME PLATES.—Primary developer: 

A. Pyrogallol 30 ¢ 230 ger. 
Potassium bromide 30 ¢ 230 gr. 
Sodium bisulphite lye 2 drops 1 drop 
Water to 1000 ccm 16 oz. 

B. Sodium sulphite, dry 100 g 7/1 8¢. 
Ammonia, sp. gr. 0.92 150 ccm 2 oz., 252 min. 
Water to 1000 ccm 16 oz. 


For use this stock solution should be diluted with 3 times its 
volume of water. The actual developer is: 


Solution A 100 parts 
Solution B, diluted 100 parts 
Water to 1000 parts 


To compensate for errors in exposure and variations in 
temperature, the following system was devised: Have ready 
in a small measure 45 ccm (345 min.) of dilute B solution 
to be added wholly or partly to the bath during development. 
if necessary. As soon as the plate is in the developer, count 


346 PHOTOGRAPHIC FACTS AND FORMULAS 


the number of seconds from the moment of entering until 
the appearance of the first outlines of the image, exclusive 
of the sky in landscapes. The number of seconds elapsing 
before the appearance of the image is the guide to the further 
development of the plate, which should be carried out accord- 
ing to the following table: 


Quantity of ammonia 


solution B diluted to % Total time of 
Time of first appear- strength to be added development including 

ance of image after image appears time of appearance 

Seconds ccm Minutes Seconds 
22 to 24 None vt 0 
foal te Ney 2 2 15 
28 to 30 8 Z 30 
31 to 35 15 2 30 
36 to 41 20 2 30 
42 to 48 gs Z 30 
49 to 55 30 2 45 
56 to 64 35 3 0 
65 to 75 40 4 0 
over 75 45 5 0 


The additional quantity of B solution must be added when 
the outlines begin to appear. 

Almost every developing agent has been suggested, but fe 
following are satisfactory: 


Sodium sulphite, ‘dry 50 g 384 gr. OV 
Ammonia, sp. gr. 0.92 33 ccm 253 min. }'} é 
Potassium bromide 6g 46 gr. yO 
Metol 4g 3g 
Hydrochinon ; I2¢g O2er. WY 
Water to 1000 ccm 16 oz. 
Or: 

Metol 6.5 g 50 er. 
Hydrochinon 210g . 16 er. 
Sodium sulphite, dry 40 ¢ * SOAer, 


Potassium bromide | 2.52 19 gr: 


COLOUR PHOTOGRAPHY 347 


Sodium hyposulphite 0.10 g 0.77 gr. 
Ammonia, sp. gr. 0.88 20 ccm 154 min. 
Water to 1000 ccm 16 oz. 


For use dilute with an equal volume of water. The small 
quantity of hypo causes the image to reverse in this solution, 
and development should be carried on until the highlights or 
flesh tones just begin to show reversal, when viewed against 
the light. Instead of using hypo, an excellent developer is 
obtained by using potassium ferrocyanide, 4g (31 gr.). 

The following is stated to commence the development from 
the bottom of the film: 


Amidol 6.6 g Slion 
Sodium sulphite, dry 19¢ 145 er. 
Sodium bisulphite lye 19 ccm 145 min. 
Potassium bromide 19to3.3¢ 14.6 to 25 gr. 
Water 1000 ccm 16 oz. 
Reversing solution: 

A. Potassium permanganate 2¢g Lion: 
Water 500 ccm 8 oz. 

B. Sulphuric acid, c. p. 10 ccm 77 min. 
"\ Water 500 ccm 8 oz. 


Mix in equal volumes just before use. The A solution must 
be kept in the dark. The following is preferable, being free 
from some disadvantages of the permanganate: 


Potassium bichromate 5g 38 gr. 
Sulphuric acid, c. p. 10 ccm 77 min. 
Water 1000 ccm 16 oz. 


SECOND DEVELOPMENT.—Any developer may be used for 
the second development after reversal; the makers recom- 
mend: 

2 Sodium sulphite, dry l5¢ 115 gr. 
» _ Amidol 5g 38 gr. 
~ «Water : 1000 ccm 16 oz. 


348 PHOTOGRAPHIC FACTS AND FORMULAS 


INTENSIFICATION.—The following silver intensifier was 
recommended by the makers: 


A. Pyrogallol 3g ZI 20) 
Citric acid 3g Za:0: 
Water 1000 ccm 16 oz. 

B. Silver nitrate 5g 84 er. 
Water | 100 ccm 3Y4 oz. 


For use add 10 parts B to 100 parts A, and immediately apply 
to the plate. The mixed solutions rapidly turn cloudy; then 
the solution should be poured away, and fresh applied. This 
should not take more than about 30 seconds, as a rule; then 
the plate should be well washed, immersed in a 2 per cent 
solution of the clearing bath, well washed, and fixed. The 
following intensifier may also be used: 


Cupric sulphate 20 g 154 er. 
Potassium bromide 20 g 154 er. 
Hydrochloric acid 5 ccm 38 min. 
Water 1000 ccm 16 oz. 


As soon as the plate is bleached, rinse rapidly, and treat with’ 
a 5 per cent solution of silver nitrate; then clear in a neutral 
permanganate bath, and redevelop with amidol or treat with a 
5 per cent solution of sodium bisulphite. 

VARNISHING.—The makers recommend: 


Gum dammar 200 g 3Y4 oz. 
Benzole 1000 ccm 16 oz. 


The following is preferable as being less dangerous as 
regards fire risks: 


Gum dammar 20 g 154 gr. 
Manilla copal, powdered 50 ¢ 384 gr. 
Carbon tetrachloride 1000 ccm 16 oz. 


As soon as the resins are dissolved, the mixture should be 
heated to the boiling point, and then filtered while hot. 
Tue Pacet PLate.—With this a separate panchromatic 


SILoUR PHOTOGRAPHY 349 


plate is exposed in close contact with the taking screen, 
developed in the usual way and fixed, washed and dried. 
From this negative a positive is printed by contact and bound 
up with a viewing screen. 

As a rough guide the exposure with f:8 in good light with 
sunshine for an open landscape is about % second. For 
portraiture, head and shoulders, outdoors in diffused light, 
f:8, about 3 seconds. Snap shots should not be attempted 
except in the brightest light at f:6.5 and not less than 1/10 
second. The speed of the plate is approximately 11 Watkins, 
F24 Wynne with filter and taking screen. A special devel- 
oper is issued by the makers, but any one may be used if 
diluted with an equal volume of water. Green light or total 
darkness must be used, unless desensitising is adopted. 

The transparency must be of a black tone, free from fog, 
brilliant and full of detail. Special plates and developers are 
made for this work. 

Tue Acra Piate.—This plate is of the combined type, 
like the Autochrome, and must be placed in the plateholder 
glass side to the lens. A special compensating filter is obtain- 
able, which may be placed in front of or behind the lens, and 
in the latter position it lengthens the focus about 1.5 mm. 
The exposure is about 60 to 80 times that required for a rapid 
plate and for a sunny landscape about midday with f:6.8 one 
second exposure should be correct. 

The developer recommended is: 


Metol Want 96 gr. 
Hydrochinon 5g 38% er. 
Sodium sulphite, dry 80 g 614 er. 
Potassium bromide 48 ¢ Ofer: 
Ammonia, sp. gr. 0.91 25.5 ccm 196 min. 
Water . 1000 ccm 16 oz. 


Dissolve the metol and hydrochinon in warm water and add 


350 PHOTOGRAPHIC FACTS AND FORMULAS 


the sulphite and bromide. When the solution is cold add the 
ammonia. For use mix 1 volume with 3 of water and use at 
18° C. (65° F.). Development time, 3 minutes. Then rinse 
slightly and immerse in the following reversing bath: 


Potassium bichromate 5¢ 38 gr. 
Sulphuric acid 10 ccm 77 min, 
Water 1000 ccm 16 oz. 


The plate may now be handled in daylight and after about 3 
minutes in this bath it should be washed for 30 seconds and 
reimmersed in the developer for about 2 minutes. Then 
wash in running water ‘for 3 minutes. Drying should be 
effected in a warm place, but not by heat. The plate may be 
varnished by gently heating first and then coating with 3 per 
cent solution of gum dammar in benzole. 


Photomechanical Processes 


The wet collodion process, collodion emulsion, lead, copper, 
and acid silver intensifiers, and reducers are dealt with in 
other sections. See index. 

CLEANING ZINC AND Copper.—For line work very fine 
pumice powder should be applied with a felt pad or soft 
scrubbing brush and water and applied in the same direction 
as the original lines of the polish. For half-tone work on 
zinc or copper well washed whiting made into a paste with 
water and a little ammonia should be used with a swab of 
absorbent cotton. Or, for copper, American polishing char- 
coal, with rounded end, may be used in straight lines with 
plenty of water. 

PASSING OR GRAINING BATH FoR ZINC.— 


Powdered alum 8125." Y, oz. 

Nitric acid Shalivasyeesy 24 min. 

Water 1000 ccm 16 oz. 
GRAINING BATH FOR COPPER.— 

Chromic acid 23 g 175 gr. 

Water 1000 ccm 16 oz. 


ALBUMEN SENSITISER FOR Line Work on ZINC.— 
Albumen (white of egg) 23 ccm 175 min. 


(Or dried albumen) 6.5¢ 50 gr. 

Potassium bichromate Sais 40 er. 

Water 1000 ccm 16 oz. 
FisH-GLUE SENSITISER.— 

Fish glue 47.5 ccm 365 min. 

Ammonium bichromate 0.132 g 1.04 gr. 

Water 1000 ccm 16 oz. 


Add enough ammonia to give a bright yellow colour. This 
351 


352 PHOTOGRAPHIC FACTS AND FORMULAS 


film must be burnt in after development. 

INKING-UP LINE Prints on Zinc.—Use photo-transfer 
ink, thinned down with very little turpentine, and apply with 
compo or fine nap leather roller. 

DEVELOPING LINE Prints.—Immerse the plate in water, 
to which a few drops of ammonia have been added, and rub 
with swab of absorbent cotton. 

Harp ENAMEL FoR ZINC.— 


Fish glue 650 ccm 10% oz. 
Fresh white of egg 130 ccm Z0Z, 
(Or dried albumen) oe 70 gr. 
Ammonium bichromate Log 115 er. 
Ammonia 15 drops 10 drops 
Water 1000 ccm 16 oz. 


Beat the albumen to a froth and mix in the glue and again 
beat up, allow to stand eight hours, then dissolve the bichro- 
mate, then add the ammonia and filter through absorbent 
cotton. The following gives a much tougher film: 


Fish glue 187.5 ccm 3 oz. 
Belting cement, Le Page’s 93.75 ccm 1Y oz. 
Ammonium bichromate 15.6 ¢ 120 gr. 
Albumen 187.5 ccm 3 oz. 
Ammonia 7.8ccm 60 min. 
Water | 1000 ccm 16 oz. 
oT 
A. Le Page’s belting cement 312.5 ccm S102 
Chromic acid 2.85 g 21.75 gr. 
Ammonia 11 ccm 87 gr. 
Water 1000 ccm 16 oz. 
B. Pure rock candy 68 g 524 er. 
Ammonium bichromate 34¢ 262 er. 


Add the acid to the water, then the ammonia and finally B 
with constant stirring. 


PHOTOMECHANICAL PROCESSES Soo 


HARDENING BATH FOR ENAMEL PRINTS ON ZINC.— 


Ammonium bichromate Deano 27 Sig 
Chromic acid 0.3 g Dao ets 
Methyl alcohol ~ 143 ccm 21/302) 
Water 1000 ccm 16 oz. 


Immerse the developed plate for from three to five minutes. 
Dye SoLuTions For FisH-GLUE Prints.—0.5 per cent 
solution of methyl violet or eosine. 
Ha.tr-ToNE ENAMEL FOR CoPpPER.— 


Le Page’s fish-glue 200 ccm 3 1/5 oz. 
Albumen 131.25 g 2 0z., 44 min. 
Ammonium bichromate Doe Zi jot 
Ammonia 33 drops 25 drops 
Water 1000 ccm 16 oz. 


Beat the albumen to a froth. Allow to stand 8 hours and add 
the glue and then the salts dissolved in some water, make up 
to bulk, and filter. 


BITUMEN PROCEsS.— 


Syrian asphalt, fine powder 42.5¢ 320 gr. 
Chloroform 400 ccm SWAY se 
Benzole, anhydrous 600 ccm 9 3/5 oz. 
Venice turpentine oe 96 gr. 
Oil of lavender 40 drops 32 drops 


The coated film should be a transparent golden colour. The 
exposure is very long even in sunlight. Develop with recti- 
fied turpentine. 

EtrcuinG Batus For Zinc.—Weak bath for first bite for 
line or half-tone, 1 per cent nitric acid. Deep etching for 
half-tones, 2.5 per cent nitric acid, 1.875 per cent for fine 
etching half-tones on zinc. For cold enamel: 

Nitric acid 15.6 ccm 4 oz. 
Alcohal, 40% 1000 ccm 16 oz. 


354 PHOTOGRAPHIC FACTS AND FORMULAS 


The exposed image is not burnt in, only heated to dry and 
harden. 
Scum REMOVER FOR COPPER.— 


Acetic acid 100 ccm 698 min. 
Common salt 187.5 g 3 02: 
Water 1000 ccm 16 oz. 


The same quantity of hydrochloric acid may be used instead 
of the acetic. 

MACHINE EtcH1nG.—Levy machine, first etch, 10 per cent 
acid for 30 to 40 seconds; second etch, 15 per cent for 1 to 
114 minutes; third etch, 20 per cent for 4 to 5 minutes. Air 
pressure for first etch, 14 to 34 lb.; second and third etches, 
1 1b. A single etch with 10 per cent acid for 30 to 40 seconds 
is generally enough except for extra deep work. For Holt 
machine and line work on zinc, 7.5 per cent with three bites 
and rolling up between. Total time for full depth, about 18 
minutes. For half-tone on zinc, use the same solution as for 
line work, for 114 minutes; then roll up and powder, and etch 
for 2 minutes. 

For half-tone on copper use perchloride of iron solution 
35° Bé. or a 35 per cent solution of anhydrous ferric chloride. 
Air pressure 4 to 34 lIb., time for first bite 30 seconds and 
total time 344 to 4 minutes after stopping out. If the iron 
solution is very acid, add a little ammonia until a slight pre- 
cipitate is formed, then boil and filter. 

CoLLoTYPE.—Grinding New Plates. Sift over the surface 
finely sifted emery powder, wet well with water and grind 
with another plate with circular motion. Wash well after 
grinding. 

Cleaning Old Plates. Soak in 5 per cent caustic potash 
solution for 4 days or place in hot 10 per cent solution of 
sodium carbonate. Scrape off old film with hard brush. Re- 
grind before use. : 


Me 


Poo LOMECHANICAL PROCESSES Soa 


Substratum. 
Whites of fresh eggs 312 ccm 5 oz. 
Sodium silicate 125 ¢ 202; 
Water 1000 ccm 16 oz. 


Beat the whites to froth and allow to settle, filter and add the 
other ingredients. Pour a little on the plate, drain slightly 
and place on leveled stand to dry. Or: 


A. Gelatine Baye: [as eae 
Water 500 ccm 8 oz. 

B. Alum 10 ¢ 80 gr. 
Water 500 ccm 8 oz. 
Dissolve the gelatine by heat, add the alum solution warmed 

up, and add 
Sodium silicate sol. 46¢ 34 OZ. 


The plates should be warmed and the solution applied with 
a broad camel-hair brush and dry. A stock of plates may be 
thus prepared, but they should be rinsed in water and again 
dried. 

Sensitive Solution. 


Hard gelatine 46 ¢ 350 gr. 
Water 1000 ccm 16 oz. 
Allow to soak for 30 minutes and melt and add: 
Potassium bichromate 16.5 2 126 gr. 


and filter. Allow 44 min. to every 100 sq. in. (682 ccm per 
square meter). Place the plates in the drying box and warm 
up to 48° C. (120° F.), carefully level and coat. The tem- 
perature of drying must not exceed 54° C. (130° F.). After 
exposure wash in water at 15° C. (60° F.) until all trace of 
yellowness has disappeared, then dry. 

Etching the Plate. Actually a moistening solution, there 
being no etching action. The plate should be rinsed in water, 
blotted off and covered with a mixture of 3 parts glycerine 
and 2 parts water for about half an hour. Or equal parts of 


356 PHOTOGRAPHIC FACTS AND FORMULAS 


glycerine and water plus 2 per cent of ordinary salt may be 
used. 

PHOTOGRAVURE.—Negatives should be full of detail and 
without hardness and preferably carbon transparencies 
should be made, showing all details in the high lights, with- 
out great density. The thinner these are kept, providing 
details in the high lights are visible, the better. - Special 
transparency tissue is issued by the makers, or standard 
brown may be used. 

Cleaning the Copper Plate. Rub over with 5 per cent solu- 
tion of potassium carbonate with cotton swab, rinse well and 
treat in the same way with 5 per cent solution of sulphuric 
acid. Wash well and polish with whiting made into paste 
with 3 per cent solution of ammonia. Rinse plate with hot 
water and dry with clean cloth. 

Graining the Plate. The usual dusting boxes should be 
used and the longer the time between setting the powdered 
asphalt in motion and the insertion of the plate the finer the 
grain. For a coarse grain wait for 20 seconds. Allow the 
plate to remain for from 2 to 5 minutes. For very fine grain 
it may be necessary to shake box and grain two or three times. 
Resin may be used but does not give such good results in 
unskilled hands. 

Setting the Grain. Grip the edge of the plate with a hand 
vice, using card to protect the copper, and heat over a gas 
flame, with continual movement so as to even the heat, until 
a steel blue colour shows. 

Mounting Resist. Place the grained plate in water at 21° 
C. (70° F.), slip in the tissue and brush the face with a soft 
brush to remove air bubbles. Bring the two into contact and 
lift from the water, squeegee well, and place between blotters 
for 10 minutes. Develop with water at 38° C. (100° F.) or 
if underexposed raise temperature to 49° C, (120° F.). 


PHOTOMECHANICAL PROCESSES 307 


Rinse in cold water and dry. If etching is to be done at 
once, flow over with equal parts of methyl alcohol and water 
and dry on whirler. 

Varnishing. The back and edges of plate should be 
painted with a 20 per cent solution of bitumen in benzole or 
Mogul varnish thinned down. 

Etching Solutions. Anhydrous ferric chloride is used. It 
is advisable to add to this 6 per cent of freshly precipitated 
ferric hydroxide, just cover with distilled water, and make 
solutions up to 43, 40, 38, 36 and 33 degrees Beaumé with 
distilled water. The following strength solutions correspond 
to the above: 43° = 46 per cent; 40° — 41 per cent; 38° = 
Beeeeeeit, oO) = 0 per cent; 33° == 33 per cent. To each 
of these the ferric hydroxide may be added, well shaken and 
allowed to settle for use, or the whole solution made up very 
strong, heated with the hydroxide and then diluted to the 
above strengths. The weaker the solution the stronger the 
etching. As soon as etching is complete, rinse the plate, 
immerse in 10 per cent solution of caustic potash and rub 
with swab of cotton. Then rinse, dry, remove grain with 
benzole, clean plate with 1 per cent nitric acid and finally 
with washed whiting and ammonia. 

PHOTOLITHOGRAPHY.—Transfer paper should be sensitised 
with a 4.5 per cent solution of potassium bichromate, rendered 
alkaline with ammonia in winter and with the following in 
summer : 


Potassium bichromate jie 4 175 gr. 
Manganese sulphate Oe 24 er. 
Water 1000 ccm 16 oz. 


Temperature of bath 15° C. (60° F.), time of immersion 
5 minutes. It is as well to squeegee the paper to plate glass 
so that it may dry with a polished surface. After printing 
place on rolling up board and apply the ink in a very thin 


358 PHOTOGRAPHIC FACTS AND FORMULAS 


film with a velvet roller. Place in water for about 3 minutes 
and then roll up again with the roller; this removes the ink 
and any slight veil can be removed with a wet swab of cotton. 
Free from water drops by lightly touching with blotting paper 
and pin to board to dry. 

DrrEcT PRINTING ON ZINC AND ALUMINIUM.—Sensitise 
with: 


White of egg 62.9 eta 1 oz. 
Fish-glue 15.6 ccm V4 oz. 
Ammonia bichromate 7.82 60 gr. 
Ammonia q. Ss. q.S. 
Water 1000 ccm 16 oz. 


Enough ammonia should be added to make the solution a 
clear lemon yellow. For large plates the volume of the solu- 
tion may be increased by one-fourth with water. 

VANDYKE OR REVERSE ProceEss.—Zinc plates should be 
grained with the graining bath given for line work and coated 


with the following: 


Fish-glue lllg 853 min. 
Ammonium bichromate 22 g 170 gr. 
Chromic acid 0.13 g lor; 
Water 1000 ccm 16 oz. 


After exposure, under a line copy, develop with plain water 
and dye up with aniline dye. The plate should then be passed 
into a bath of: 

Ferric chloride, 31% sol. 2ccm 16 min. 
Water 1000 ccm 16 oz. 
Leave the plate until the colour disappears, then rinse and 
dry. Treat the plate with asphaltum washout tincture, and. 

ink up with the following: 
Bitumen, powdered 4 parts 
Litho chalk printing ink 1 part 
Litho writing ink 1 part 


Peo lOMECHANICAL PROCESSES 359 


Burgundy pitch 1 part 
Mix with heat and thin with the minimum of turpentine. 
There must be but a very thin film of ink on the plate. 
Allow the plate to dry and develop with water, plain or very 
slightly acidulated with hydrochloric acid. 


Weights and Measures 


RULES FOR THE CONVERSION OF WEIGHTS AND MEASURES. 

W erghts.— 

Grains to grams: Take 6 per cent, and add 8 per cent. 

Grams to grains: Multiply by 15, then increase result by 
3 per cent. 

Ounces to grams: Multiply by 28, then increase result by 
1% per cent. 

Grams to ounces: Take 3 per cent, and increase it by 
1/6 + (5 per cent of 1/6). 

Pounds to kilos: Take 40 per cent, and increase it by 
10 per cent + (1/3 of 10 per cent). 

Kilos to pounds: Multiply by 2, then increase result by 
10 per cent + (2 per cent of 10 per cent). 

Lengths.— 

Inches to centimeters: Multiply by 2, then increase result 
by 25 per cent + (8 per cent of 25 per cent). 

Centimeters to inches: Take 40 per cent, and diminish it 
by 1¥4 per cent. 

Yards to meters: Take 70 per cent, and increase it by 
30 per cent + (2 per cent of 30 per cent). 

Meters to yards: Add 9 per cent and 4 per cent of 9 per 
cent. 

Fluid Measures.— ‘ : 

Pints to liters: Take 40 per cent, and increase it by 40 per 
cent + (5 per cent of 40 per cent). 

‘Liters to pints: Multiply by 2, and diminish result by 
12 per cent. 

Example: Required the number of grams equal to 15.432 
grains: 


360 


WEIGHTS AND MEASURES 361 


6 per cent of 15.432 =0.92592 
8 per cent of 0.92592 — 0.0740736 


0.9999936 
The result should be 1 g, and the error is less than one in one 
hundred thousand. In all the above rules, in no case is the 
error greater than one-thousandth. 
Table to convert grams per liter to grains per 16 ounces.— 
G per liter Gr. per 16 oz. G per liter Gr. per 16 oz. 


1 7.68 10.5 80.64 
Lee iio? i 84.48 
Z 15.36 11.5 88.32 
20 19.2 12 92.16 
3 23.04 ae 96.0 
oS 26.88 3 99.84 
4 30.72 130 103.68 
4.5 34.56 14 107.52 
D 38.4 14.5 PSG 
aps 42.24 15 Se 
6 46.08 15:5 119.04 
6.5 49.92 16 122.88 
7 53.76 16.5 126.72 
7 57.6 17 130.56 
8 61.44 17.5 134.4 
8.5 65.28 18 138.24 
9 69.12 18.5 142.08 
9.5 72.96 19 145.92 
10 76.8 195 149.76 
20 153.6 


To find the number of grams per liter, divide the number 
of grains per ounce by the following factors: 
2 ee Cr per liter Oz.) G per liter 
1 0.48 10.5 5.04 


362 PHOTOGRAPHIC FACTS AND FORMULAS 


1.5 0.72 11 5.28 
2 0.96 Liss Sate 
Vat Le 12 m7 
3 1.44 es, 6.0 
3.0 1.68 pan 6.24 
4 192 133 6.48 
4.5 2.16 14 6.72 
5 2.4 14.5 6.96 
aD 2.64 15 in 
6 2.88 15 7 44 
6.5 3.12 16 7.68 
7 3.36 16.5 7.92 
fied 3.6 L7, 8.16 
8 3.84 17.5 8.4 
8.5 4.08 18 8.64 
: 4.32 18.5 8.88 
9.5 4.56 19 9.12 
10 4.8 19.5 9.36 
20 9.6 


Approximate rule to convert English weights and measures 
into metric: 

1. Call the new volume of solvent 1000 ccm. 

2. If any of the ingredients run to ounces, take their ratio 
to the solvent, and write down the same ratio to 1000 in 
grams. | 

3. Divide each grain item by half the number of ounces, 
and write the result down in grams. 

PERCENTAGE SOLUTIONS.—Some dispute has prevailed as 
to the exact meaning of “x per cent solution,” but in photo- 
graphic practice it means x parts in 100 parts of the total bulk 
of solution. As most chemicals are sold by the avoirdupois 
ounce of 437.5 grains, and liquids are measured by the ounce 
of 480 minims, some confusion has arisen. The following 


WEIGHTS AND MEASURES 


363 


tables show: (a) the accurate quantities of solids to be dis- 
solved in sufficient liquid to make a total bulk of 100 parts for 
the various percentages; (b) the number of grains to be dis- 
solved in sufficient solvent to make 1 ounce of any given 


percentage. 


1 per cent 


66 


WO ONDA wT BW DH 


10 66 


66 


The number of grains of a solid which must be dissolved in 
sufficient liquid to make 1 fluid ounce for the various per- 


centages : 


1 per cent 


66 


WO OND wh W DO 


10 ce 


6é 


ce 


4.8 gr. 


Dae 
14.4 “ 
Laie 
24.0 “ 
28.8 “ 
3.01% 
88.4% 
43.2 “ 
48.0 “ 


These tables are sufficient to calculate any percentage or 


volume, by merely multiplying or adding. Example: 


Re- 


quired to make a 15 per cent solution, how many grains are 


required : 


364 PHOTOGRAPHIC FACTS AND FORMULAS 


10 per cent = 43.75 
5. per cent = 21.875 





65.625 gr. 
Required 16 oz. of 10 per cent solution, how many grains 
required: 
48 X 16 = 568 gr. 
The following tables are sufficient to enable anyone to read- 
ily convert the metric into the customary units, and are based 
on those published by the U. S. Bureau of Standards. 


Lengths.— 
Inches Centimeters Inches Centimeters 
0.3937 = | i = 2.5400 
0.7874 —=2 rs = 5.0800 
1.1811 = 3 3 = 7.6200 
1.5748 = 4 4 = 10.1600 
1.9685 = 5 5 = 12.7000 
Zio0ee = 6 6 = 15.2400 
2.7559 =/ Zi = 17.7800 
3.1496 == § 8 = 20.3200 
3.5433 = 9 9 = 22.8600 
Areas. — 
Square Square Square Square 
Inches Centimeters Inches Centimeters 
0.1550 = 1 1 = 6.452 
0.3100 = 2 Me = 12.903 
0.4650 = 3 " = 19.355 
0.6200 = 4 4 = 25.807 
0.7750 = 5 5 == 32.258 
0.9300 = 6 6 = 38.710 
1.0850 = /7 7 = 45.161 
1.2400 == § 8 = 51.613 
1.3950 =9 9 == 58.065 


WEIGHTS AND MEASURES 365 


Masses.— 
Grains Grams Grains Grams 
1 = 0.0648 15.4324 = 
fs = 0.1296 30.8647 = 
3 = 0.1944 46.2971 = 
4 == 0.2592 61.7294 = 
5 = 0.3240 Re / 2c = 5 
6 = 0.3888 92.5941 = 6 
Ai = 0.4536 108.0265 = 
8 = 0.5184 123.4589 — & 
9 = 0.5832 138.8912 —9 
Liquids. — 
Cubic Cubic Fluid 
Centimeters Minims Centimeters Ounces 
1 = 16.230 29.574 = | 
fo = 32.460 59.147 = 2 
ss = 48.690 88.721 = 3 
4 = 64.920 118.295 — 4 
S = 81.150 147.869 = 5 
6 = 97.380 177.442 = 6 
Z = 113.610 207.016 —=/ 
8 == 129.840 236.590 = §& 
9 = 146.070 266.163 —9 


The U. S. gallon = 3785.43ccm; one liter = 33 fld. oz., 
391 min. 

The above tables apply to the English weights and mea- 
sures, with the exception of the liquid measures; the English 
gallon measures 160 fld. oz. = 4545.96 ccm. The following, 
therefore, must be used for conversion of the same: 


Cubic Cubic Fluid 
Centimeters Minims Centimeters Ounces 
| = 16.894 28.4123 — 1] 


2 = 33.788 96.8245 = 2 


366 PHOTOGRAPHIC FACTS AND FORMULAS 


3 = 50.682 85.2368 =3 
4 = 67.576 113.6490 - 
5 — 84.470 142.0613 — 
6 — 101.364 170.4735 = 
7 — 118.258 198.8858 _ 
8 — 135.152: 227.2980 = 
9 — 153.046 255.7103 — 


CoMPARISON OF THERMOMETER SCALES.—Equivalence of 
Centigrade (Celsius) and Fahrenheit Thermometers. 


Oenti- Fahren- Centi- Fahren- Centi- Fahren- 
grade heit grade heit grade heit 
0 32.0 35 95.0 70 158.0 
1 33.8 36 96.8 71 159.8 
2 35.6 37 98.6 72 161.6 
3 37.4 38 100.4 73 163.4 
4 39.2 39 102.2 74 165.2 
5 41.0 40 104.0 75 167.0 
6 42.8 41 105.8 76 168.8 
7 44.6 42 107.6 77 170.6 
8 46.4 43 109.4 78 172.4 
9 48.2 44 111.2 79 174.2 
10 50.0 45 113.0 80 176.0 
11 51.8 46 114.8 81 177.8 
12 53.6 47 116.6 82 179.6 
13 55.4 48 118.4 83 181.4 
14 572 49 120.2 84 183.2 
15 59.0 50 122.0 85 185.0 
16 60.8 51 123.8 86 186.8 
17 62.6 52 125.6 87 188.6 
18 64.4 53 127.4 88 190.4 
19 66.2 54 129.2 89 192.2 
20 68.0 55 131.0 I 194.0 
21 69.8 56 132.8 91 195.8 
22 71.6 57 134.6 92 197.6 
23 73.4 ii) $8 136.4 93 199.4 
24 75.2 59 138.2 94 201.2 
25 77.0 60 140.0 95 203.0 
26 78.8 61 141.8 96 204.8 
27 80.6 62 143.6 97 206.6 
28 82.4 63 145.4 98 208.4 


29 84.2 64 147.2 99 210.2 


WEIGHTS AND MEASURES 


149.0 
150.8 
152.6 
154.4 
156.2 


100 
105 
110 
115 
120 


367 


212.0 
221.0 
230.0 
239.0 
248.0 


Chemical Tables 


TABLE OF SYMBOLS AND MOLECULAR WEIGHTS OF 
THE MORE IMPORTANT COMPOUNDS USED 
IN PHOTOGRAPHY 


Mol 

Name Symbol Weight 
Acetone .:....ccevescececescess , Os Ele igen ene 58 
— sulphite .......+seceeee C, ep OH. SO..Naee eee 162 
Acid acetic siya ae ot eine eee aie 2 Hy Os cA ae 60 
mae! PEN ZOIC 05 seeciou Sica ere nai Cs H, COOH 23332. 122 
soe DOLICGS cise DUE os ee Ee Hs BOs a ble) @ a 00 10° 6) © oly le Wane eteie 62 
woe CAPDOLIC Gy ang eee eee C..Hs OH vas ee eee 94 

— .chlorochromic /....).s.e:.- Cl Cr 0; OF 2a 136.5 
— chromic (anhydride) ..... t Op’ ovine ck seen eee 100 
a CHIC ee ane CEs C. Hs O; HsO°70 eee 210 
ttt ITNIONIC Faia Vinee cn ements a 7 et bs deeaak eee 162 
—- ‘fOrmic ..c...cecececsceese fda COs oe 46 

— gallic ola aie s¥\ are ee) 679s eles © etal @: i “oH. COOH, H:0 . 188 

> hydrobromic: ones anee rene Br .vs.ssciau s Se 81 

aoe! hyd rochloricuast. san een ore H.Ch co ee 36.5 
HV OLONUOLIC: toatecikin oy es FE opiates ee 34 
cmt MACHO We ots Ae eaten Lee CH; CH (OH) COOH] 90 
joues IETIOL SEE on aro eee HNOs 225.154. 63 
we, ORAL eee ea een ere He Cz Ong was Sees eee 126 
—— | pentathionic:c'..4 o. caine ee H, Ss Os 2 isos sneeeeeee 258 
=>. Perchromic o.seek teen eee H Cr Og ee cee 117 
= ‘phosphoric: . 5.\ ays Meera Hs POs« .sit sau 98 
— picric Coe eee rece erceresace C. H: (NOsz)s 0) s Bey 139 
—-\pyrogallie. 2) c5ic. eee e H) so. eee 126 
mos SALCVIIC ca wat eee tenn Co Hi, (OH)-COOR- 2. 138 
— +s sulphuric. a0 sei cme teats Hs SO« cece se clause nee 98 
=) SUlphurous: (7) Se ste ee H, SO oso ye ee 82 
mes SATINIC } SS Uh clea are Cu Hy: Os see ee eee jee 
~—>' tartaric. 00 ee eee C. H: (OH): (COOH), 150 
tetrathionic ». yee: eet eee Hs Sa OO See eee 225 
=o! trithionic <a hee eee eee Hs: Ss Oe ses. eis ee eee 194 
Alcohol: (methyl)... ese eee CH: OH 75.8 Sine eee oe 
ak Gath yl) Lie ote eee C, H; OH) a eee 46 
Alum, ammonia... eee Als (NH,): (SO.)4 24H:0 . 906 
oan): Chroinie Vs.) de cour ome ates Cr. Kz (SO.)s 24H:2O ...... 998 


iron ammonia 


potash 


Ce 


Fez (NHg):2 (SO.)s 24H:0 . 964 
Al: Ka (SQs)« 24H2O 948 


368 


eseeeoee 


Chm MICAL TABLES 369 


Mol. 
Name Symbol Weight 
Aluminium chloride ............ la Gletl eg rls) cates s 267 
— CELE Tl re Ala (Os) es LOHsO in wna es 634 
— sulphocyanide ....... Pulse CON Vl av tnticumanas os 402 
Me ca kesh is os a ve GHeOH ONE) scHCle 2197 
Co NTE ES DN Fis ete conosco ee 17 
Ammonium bichromate ......... CNTs ors Oras oh np sees ale tone 
— RRS hoa 5's vie ams INTER tare nia cee an nalas 98 
_— a ne ee eC rans COOH 
— CMlOrine? Bs ibs vias s Dg Ppl Oy Eekilete eu ceae maar yew nat, ete Sod 
— PIA COS oe icin ee o's CNT nC. pees 2 152 
— TEAL cers eee o's eat oe BD heel Oat AR a eae eget | 226 
-— IMU SS at's 5 5 YS PL eagles are Peto apa creole 145 
—e molvhdate. .v.6.5<5' (NH,)»6 MO; Ou 4H20 . SAS 
— RMR LOM sc fac se Ls.0'<58 IN EE EIN gees eeeelete ater 80 
a Wh ae (NHsg): BAO Fa sO tech apes 142 
— persulphate ........ CN scat auen ois rie ee 228 
— Phosphate... s.e.s0s GNE elastie Olesanatie se weceens 132 
— Sil piatO ss. o po« sve CINE Ven, SQ cate ce aries 132 
— BUONO s <4 7: be cas ee DATS bet hinder said en deen 51 
— sulphocyanide ...... IN FIR GIN Serene ens ture 76 
— Wate ons a oc os DEEL, AVh ater ke jecescc kel Soe 117 
CCT CI et a Cpr ee i oe oe cee 130 
co UGS "0 ne a (CH;:)2 CH CH: CH.0H .. 88 
Aniline GHewursteOe susie shevanerels sls s. 96 0 6 ¢ Ce H; NH; ahetertabeleratehcharstenatens 93 
Antimony, sulphide ............ Sbeposyic nite wee Satie OOO 
IAS eto 5 Aaa, nae ae (CoH2(NO2)s)2 N NHz .... 456 
eS isle ade oc 4 9.0'% 9:0 0.0 c (Ce Hg OH): CeaHvOs. 22290 
PeaE EP OTOMNAG os. dbs s sees as Pap bishe bis era eek tae 333 
PeeM CIMONICG i 6c csc cbs eae 0 Baa Zl) he ee ak 244 
SRMOUIGC io oh cere ce wes Dak gene vc awel tes Rhea eee 391 
RIVIZVACE loci viy cis ae > 4 ss 00 BSA. (Oe ha eites ca aeataene cates 261 
Se gp al 6 | a a Oe Rane er seen 201 
Dem SINDAtG ie ca wees ess Day OORT IOS ee eae 233 
Benzole (benzene) ............. Py PRE I hin LA a hair 78 
Borax (see Sodium Borate) 
UCD ARID oy cos va ee 1 habia care is oe aie Aa ae 80 
adam, Dromide ..........60% UdoB ra FiO eae 344 
— iat (C7 Lge ee Che acre hae erie aed couhieseteas 183 
— MERU Che 54 oop ius woo 0 Cal es Nr cael ita ie . aetenees 366 
SOLOS. fel tg 0) G (ae OPER OF tein tenes hare MOR T oe a 64 
— TON ELO IF cicere 4 sia'e goes Cas Oe eer nask te foes 100 
— enioride Ceryst.) ...... Carl Orso sn ries cre oe 219 
— chloride (fused) ...... Cat Clie eience i iaets eon 111 
— hypochlorite... .5...55. hee CET) greene a Sens 153 
— BUSES d. ci <diaivre es Camel ie aeetnr see ae 172 
enernyaroxtde slaked lime) (Ca (OH)s ...0:.0.00-00000 74 


370 PHOTOGRAPHIC FACTS AND FORMULAS 


Mol. 
Name Symbol Weight 
Carbon, bisulphide®... sis. sens « ORR es 76 
Celigidin yc a icn cn concn beanie ae Cis Hie Oc (NOs)« cece eeene 504 
Ceric” sulphate. is: sta a ok ans Ce -(SO.)s)4HiO Wie eee 404 
Chioral hydrate 25 200. ct viscce'a otets C Cl. CH (OH )s5272e07e 165.5 
Chinroforniiey 4 cheese kee orcs eens CH: Cls. 3. 119.5 
Chrysoidine eevee cvcccccecceees Cs Hs N: Cs Hs (NH:):; Mew Rie uean 
Cobalt chlorides: ... ose as secs tens Co Cl.:6Hi0 32. ee 238 
Coppet,: bromide U0. si. 2 vce Cu Bra) ou. eee ee 223.5 
an CHIOTIAE! os eens cv eee eves. Gu Cl 2H ae eee 170.5 
eon il MUTPALE Pec ey cee sees Cu (NO;)16H,0 3a 357.5 
cent’ & SUIPNALE (5 weet sche slatercints Cu SO, 5H30O Ge ee 249.5 
CSyatine 45 cS 54 te aabeete mene es Cos Hes. Na Di oc ee eee 544 
Dextrine os eek: a eee eee (Ce His Os)? aa eee — 
Diamidophenols: sco. on wta ca sist she CoH: OH (NHas)a seen eae 124 
FGRINGses Parks ee cone ean Na or: K. Salt. ot aii eee 
CeH.(CO)20(CsH OH X*), — 
Erythrosine /\ sist ee eee CoHi(CO)20(CGHOHX2*)2 = — 
Ether (ao ney Se alate eee eee eae C, Ha: 0 60 eee 74 
Ferrous and ferric salts (see Iron) 
Bormatitiey Wooo ce cles aie coches 40% sol/ of CHsO finesse —_- 
Glycerine sos hele oe eee Cy; Hs (OH) sy. ee eee 92 
Giron t 7 oi ge pce ee eae C. Ha OH NHCH; COOH . 167 
Gold, chloride yellow .......... H Au-Cl 4Bg0 ae 412 
— os DrOWIlO ; esc eae H Aw Che: cess Seas ee 340 
— — potassitim. hn 5 we K. Au’ Cl, Z2HsO- eee 414 
— — soditttiy. ¢ avns sees Na An: Ch 2HiO one 398 
Hydrogen, peroxide ............ HiaQOs «ib isne cance nee 34 
Hydroduindne! ee eee ocne cee Ce. Ha (OH)s 2a eee 110 
Todines ones os ui patents cote eee | RPE re Ga 127 
Iridious chloride 0: 4.2% «assent Ir Cle coe core a eee 299.5 
— tetrachloride ........... Ir Ch. st .2 eee 335 
— potassium tetrachloride . K; Ir Cle 2,24. seus eee 484 
— sodium tetrachloride... Nas Ir Clea: sen sse eee 452 
TRON. 
Ferme chloridé: (dry) 4c. eae Fes Cle ss. ine) wap eee 325 
— chloride (lump) ....... Fe, Cl, ZH ees eee 541 
— ammonia citrate, brown 4 Fe Cs Hs Or 3(NH4a)s Co 
H;O; 3Fe (OH): eo cccene 2030 
ee aes — green SFeCsHsOr2 ( NH.) sCoH,O.N 
1,0; 20 ,OF ae 1956 
=) Oxalate oh 5's clea ae ws Nios Fea ie O.)s eee renee ccce 376 


* The X in these formul# may be bromine, iodine, or chlorine, which 
elements in other proportions constitute the various commercial dyes. 
¢ Glycin is y-oxyphenyl-glycin or y-oxyphenyl-amido-acetic acid. 


CHEMICAL TABLES 


Name 
IRON. 


Ferric Ammonium oxalate .. 


potassium oxalate 
sodium oxalate 


PECVSE) 651. « 
Th A Se 
potassium oxalate ... 
sulphate 


ammonia sulphate ... 


Lead, acetate 
nitrate 
Lithia, caustic 
Lithium, bromide 
carbonate 
chloride 
iodide 
Magnesium, chloride 
sulphate 
Manganese, peroxide 
sulphate 


eeereoevveevevee ees eeee0 
e@oeoeveeseeeeeoeeeeo ee 
ceoeeeeeeresee eee eee 
eooeeeose eee eaeee 8 
ae 
eeereeveveeevee ee 

—= 


eecevveeeeeeeee80 


—— t 
eeovoeeveeeeeeev eee 


eeovoeeeveesed 
—— 

oeoeeeveceeeee 
eeeoveeveveee8@ 


eeoseeeeveevee 


eoeoeceeeeeoeeseeeereeeeeee 


bichloride 
iodide 


eoeveveeeveeee seve 


Metol* 


Palladious chloride 
potassium chloride .. 
Fara-atndopnenol ¢......606.00 
Phenol (see Acid, carbolic) 

Platinum per (or bi)chloride ... 
Potassium, ammonium chromate . 
bicarbonate 
bichromate 
boro-tartrate 
bromide 
carbonate (dry) .... 
chlorate 
chloride 
chloro-platinite 
chromate 
citrate 
cyanide 
ferricyanide 
ferrocyanide 
hydrate 


eeenveeeee 


e@eeeeesee 


eeceoeevee 


eooeeceee eevee 


eevee 


Poesia oe iota 


371 


Mol. 
Symbol Weight 
(NHa)s: Fe (Ca Oxz)s 3H20 . 428 
K; Fe (Ce O.)s Db si sad eee 491 
Nao Fe (C204) 6 Lio... 976 
bE SDS re PB ee Pees i ga ar 127 
ECC IPA LA ee aes ese 199 
RC LOA ard 5 Dane are 180 
K2 Fe (C2 eae igs ise) allele 328 
Beis a) ew cass cane 278 
Fe (NHag): (SO.)2 StisC eee 
Pb a Hs O:2)2 3H: a, ae aes 379 
Ns Jal el atemc apr ns atace ke 331 
PSIG) Elie ere ay ete ates nie alee: ag 24 
Deeds Pe Sor grey a's Sal comin ia 024 87 
Pe Oe tae iitae nae cet ee 74 
i ts (cryst. has 2H2O) . 42.5 
CIRC AON RIE OR nce , 134 
Me ek Ba Petals debsiata weiesatetoeets 95 
Me SORTA SE Gi tee sar eore 246 
It ed elie ea Pete aeran oped ae eR 87 
Qatar is), ck ees tases 225 
(CEN treet Ce DR ee ee 200 
EL Ria ted eee ed ate hig a SE 271 
(in Fd Bvt 220 ea aA eS 454 
U2 OS P83 8 Wes cee ee tee 786 
(CeHsOHNHCHs:p):H2SO. 344 
Et lea eyes na Sie ep eatwlet is 177 
Ae it Oe eee 326 
RAG EES AU Eres avers wiciad ss 109 
By Pte ClsGFO to ie 516.4 
RON Ee Gr) aati e c'apeene lp 173 
K is oe Drea kewl aeny ae 100 
HK: oath eect 294 
ce na (OH): (CO:)2 BOK . 214 
Eves se cece eae coats: 119 
| Arp ORD) ae Bes pees ip tarred rate 138 
Ota cee ai ease ieee cet With 
BiG eel oaedas Sa haa ones ania 74.5 
Pps lg he ette te tee ae ces cate 413.4 
Ia PO ga artery ca areae | 194 
OU Or eh Os BO al ceinrp ore ae 
Bare COND wiry oe cas hs 329 
K, ae (CN) a 3HsO7.......s gee 


* Metol is the sulphate of mono-methyl-para-amido-phenol. 


372 PHOTOGRAPHIC FACTS AND FORMULAS 


Mol. 

Name Symbol Weight 
Potassium, i006 wee. ven es Gh GN ee 166 
— metabisulphite ...... Ky S;3 Os Soe 222 
— HitrAtene Ost oe ecto « K NO3g vol. es ee 101 
— Hierites sn yas close ate K NOs: i... eee 85 
— DORAL rouse recs K; CC, OHO} ee ee 184 
— percarbonate... 6.5 Kya Cs Oo 2p soe ee 198 

— perchlorate .2.55....- KCl Oc (a3 or eee 138.5 
— permanganate ....... K; Mn; Os 2) oee3 ee 316 
— persulphate ......... K, Ss Os <0 ee ee 270 
Siulphate i eouack cies es K2SO4 sdetails eee 174 
eaiphocvanide HAART ee ete oe K CNS sienna 97 
Pyrocatechin #.0.% ncn eee ae Ce Ha (OH) 3 cea eee 110 
Rochelle ‘salt oor oie eeielateies « K Na Cy Hi O¢ 4H 282 

Schlippe’s salt (sodium sulphanti- 

MHONIate,) 2's Coes te ind te eee Na: Sb Si 9H:Oo eee 479 
Silver acetate ..cncet woe ees Ag CG, He Os5.05 oa ee 167 
— ammonium nitrate ...... Ag NOs +2NHa eee 204 
ave! oh bromide. iitrae Gee ae te Ag Bronce eee 188 
nan. CAT Donate 47 ancien san Aga COs\.ni2s ee ee 276 

woe CHIOLIGE sears conte oe aes Ag: C's... 3 eee 143.5 
mae OUELATE Veh eee Aen Ag: Gs Hs Oro See 513 
erik UOLIGeM Nl duten ts nateeene Ag F 4H;0; 05.5 0.3 eee 199 
mei TOCIUE! (ects sc ah sete Eee ae Ag I ..wS0% eee ee 235 
sor MALALEY Sie ee Ag NOs. 2405.4 ae ee 170 
mem} TUETIL@ os bo anise Ag NOs °:48 20) ete 154 
moe OXalatE Hiusgklossae so niree Ag, C, OV eee 304 
aout |. ORT an incite segeewas eerste ante Ags O ds Meee 224 
-— | phosphate). pice. ae, Aga POW. 2 ek aoe ee 419 
os tt «SHI DHAT@ ak as Gs ole cee Ags SQyci ieee eee 312 
ants SUL PDIGE %(eesivitnee tee tate Aga 8 wou oes pen a 248 

sai LAATEPATE! icin atels Meecha meets Ags Ce Hy Oe see 363.4 
Sodium: acetate yiu)wiswetae eee ae Na C, H; O23H:0% eee 136 
— ann CSteged) ewe Na C; HQ) esa 182 
=. ‘bicarbonate eet tous eves Na H: COs. ae eee 84 
—  bichromate ............ Na; Cra QO; 2H;0 2 298 
—  bisulphite ..... SE As) Te Na H SOs 232 104 
==: borate j)ccuiyaeb eee Nas Be Or 10H:0- 635s ee 382 
ao bromide? vacua. ewer Na Br: 2H.0° 232.32 eae 139 
— carbonate (dry)* ...... Naz COsicAtikic eee 106 
— carbonate (cryst.) ..... Na: "GO; 10H,0O.0 3 ee 286 

re’ Chioride ea, see eek Na. Cl .ccwen ee 58.5 

— chloro-platinite ........ Naz’ Pt Ch’ GHG ee 560.4 
rove Citrate Alice ctr eee Nas Cs Hs O; 5%4H2O ...... 357 
we 1, HUOTIGE | eos yc ee Na Fo. 42 


* In formule 10 parts anhydrous (= dry) soda carbonate can be used in 
pee me 27 parts cryst. soda carbonate. 10 parts of cryst. equal 3% parts 
oO e dry. 


CHEMIGAL TABLES SVs. 


Mol. 
Name Symbol Weight 
Rates ivcrace (caustic) .... Na OH) ....cccee ve cecs sees 40 
—  hydrosulphitef ......... Na EIS Chae tats ences et ree 88 
—  hyposulphitet .......... Weve Ca fal EOy Ae Gar aneen 248 
SRPSCUG LG iia gioco vic tases Navleteen tien aeicak Mate choke 150 
BPTI CRO Ge le vac cae ss ss Naan Gg Gate car corer oy Be 85 
—  nitro-prusside .......... Naz Fez i CN). (NO). 4H20 600 
BROOM AAC Y Caco cclciacessces Nash ae Cina een norte cee 134 
Beer DNOSPNAtG ~......0..006. Nast ROG IZEOm i ia stan 358 
—  tribasic phosphate ...... IN eee SLOT a Jee cies sixls eras 380 
Peensiipnate (Cryst.) ...... DEP AST Fed (Uli FO Biase gagn Pare goes 
EC RULOMIGE giv. cesses Genes Nase OR OE AO are oy hace ees 240 
—  sulphite (dry)§........ Nig gee outa ie gina nee 126 
— SS.) ite 26) 2 ee Na goOr LA dale ori asim Zo2 
Peat States... ct ce oes Nai Wis Oa 28H3O So. ee 3598 
eeromuum, bromide’ ............ Stele perk eee Ore oats 247.5 
— eiorides( dry) os. . +. ene Lod by Be Narang Wage eter atte 158.5 
— Reet SU) stan Or Ch 20 oi vice aces 194.5 
— UMEIGO Ue oe os isco s/h SS EUiha teed etiehers clades a alate 6 Ui 341.5 
— BOAR a otis ia ed sins ST eR DAs anmtnieted ase e ular arate Zins 
MOCAPDATINUG 6.506556 00000000. (Sy i Be Pe rye A lah hes re 76 
SMSIGAITITNG 6. cao ge  esiviee ee es CIN Elson ok Moa ete ta am 116 
Thymol Sieislrede el alievieliei ble) se) clei els), 'e ale CH; Cs 1 Pla Bs ies Ory S PG noe 150 
Tin (Stannous) chloride ....... Dyifeelamre te) ee casas 225 
Dirannime acetate ........66..5.. UO, ie H; O:)2 2H20 .... 426 
_- BI IUC Mr fers sas ks ce LGPL ONE, oes yee anempeus mo wee fd ie ae 343 
SN THEDALC. fas. ce et ee es UO: (NOS: CHO sree: 504 
fon te, 10 Nh Dili OAL aon ieee 287 
A TABLE OF ATOMIC WEIGHTS OF THE CHEMICAL 
ELEMENTS 
Atomic Weight Accurate 
in Round Atomic 
Name Symbol Numbers Weight 
5 aR Al 27 27.1 
Sea en Sb 120 02 
LO SI eo A = Al) 39.9 
Be os ew sees « As 75 75.0 
rem Ee  es elc acces 6 a5. Ba 137 137.43 
BROS feck stain ce ee es Be = Gl 9.1 9.1 
“OSL qa Bi 208 208.0 
SL 9 2 er B 11 11.00 
ES Se Br 80 79.96 


~ Called ‘‘hyposulphite’’ by chemists. 

t Called ‘‘thiosulphate’’ by chemists. 

§ In formule, 1-part of anhydrous (= dry) soda sulphite can be used in 
place of 2 parts cryst. soda sulphite and vice versa. 


374 PHOTOGRAPHIC FACTS AND FORMULAS © 


Atomic Weight Accurate 
in Round Atomic 
Name Symbol Numbers Weight 
Cadoniiin Nineties eoitee estes Cd 112 112.4 
CSIR ecg euien see eee ee Cs 133 132.9 
CATE MIPRL AUS a lots cl ta Aa le nl ot Ca 40 40.1 
Ciarhonce ee yee to cistia sae oie Cr 12 12.0 
COP HTE Lo rdicg Ge acres keene Ce 140 140.25 
Chlarsneoee cae Cota cue a's ole Cl 35,5 35.451 
Chromite sieue sk cae reste oe Cr 52 52.11 
Cera Lend wean an ek ce Gon ware ee Co 59 59.00 
SON DER os Vl eee e nate Cu 63.5 63.60 
Ferbatted $s )hhs 5 cates sete ke Er 166 166.0 
PEGGING Aap have eine kere F 19 19.0 
Gadolinium (520 Foe ol a Gd 156 156.01 
pal Titans SOP ae pase eae ig cies Ga 70 70.0 
(réfmaninth); Tet weeces ee Ge Pons 720 
Croley Por ek ieee eee cees Au 197 197.2 
Fleurs? Sop fhe ve He 4 4 - 40 
Tivdtocenin: sac sateneaenen i 1 1.008 
Tdi hid elas Sheek ei ee ites 115 115.0 
TONE Wis exes etna I 127 126.97 
Letdinar yer Oe pene Ir 193 193.0 
Tet Or Reha teeta ae Fe 56 55.9 
Tsaritiaa riitey is tu as khan ets La 139 138.9 
LMA as ya ipieaelae ee cneie Pb 207 206.92 
Datu eat ae eae wee Li 7 7.03 
Magnesini i... 3 gnc Seow ees Mg 24 24.36 
Manvaneses) cence Mn 55 55.0 
Merciry.te sk catikcs as sino e Hg 200 200.0 
Molybdenum it. e304 Gace ces Mo 96 96.0 
Neodymium \) 3. a peas Nd 144 143.6 
Nickel Gay ee Gece tee Ni 59 58.70 
IUIODILIN Gs ic ueik es auc ine pees Nb = Cb 94 94.0 
INNECOMOT TY OGh oui here nine aetna N 14 14.04 
Cistritiin 25.5.0. y ae ee pans Os 191 191.0 
Oxygen (Standard) . 01065. O 16 16.0 
Palladium. .coy eevee eee Pd 106 106.5 
Phosohorus acs cee ss eee P 31 31.0 
Platinuini 23a. 528 eee ene Pt 193.4 194.8 
Potassium so eeu becrrb ss te K 39 39.15 


Praseodymitm 0... 2. ean es Pr 141 140.5 


Rhodium . 
Rubidium 
Ruthenium 


Samarium 
Scandium 
Selenium 
silicon... 
Silver ... 
Sodium .. 
Strontium 
Sulphur . 


Tantalum 
Tellurium 
Terbium . 


Sdtitiiats «5% 
Titanium 
Tungsten 


Uranium . 
Vanadium 


Ytterbium 
Yttrium . 


Ae 6s 3s 


CHiuMICAL LABLES 


eooeeeee eee eee eeeos 


eoeee eee ee eeeoe ee ee 


e@eeveeeeoeeeeea eevee 


eeeoereveeeseeeveeve eve 


eececereeseeeeeeseese 


eoeeeseeree eee eee eee 


eeeoeveeeveeese ee eee 


eeeoeeeeve ee sere 


eeeoeeeeeee eevee ee 


eeovoeeeeveev eee eee 


eeoeoceveceeeeees eevee 


eoseceeoeee eevee eee se 


Symbol 


Atomic Weight 
_in Round 
Numbers 


375 


Accurate 
Atomic 
Weight 


103.0 
85.5 
101.7 


150.3 
44.1 
79.2 
28.4 

107.93 
23.05 
87.6 
32.06 


183.0 
127.6 
160.0 
204.1 
2320 
171.0 
119.0 

48.1 
184.0 


238.5 
51.4 


173.0 
89.0 


65.4 
90.6 


Appendix 


EASTMAN Piates.—After June 30, 1924, the distribution 
of Seed, Standard and Stanley Plates will be discontinued by 
the Eastman Kodak Company. The new Eastman Plates 
listed in the left hand column can be used for the same 
purposes as those formerly supplied, which plates are listed 
opposite in the centre column. The approximate relative 


speeds are given at the right. 


Eastman 40 Seed 30 
Eastman 36 Seed 26X 
Eastman Speedway _— Seed Graflex 
Eastman Process Seed Process 
Eastman 33 Seed 23 


Standard Extra Imperial 
Stanley Regular 
Eastman Polychrome Standard Polychrome 
Eastman Commercial Stanley Commercial 

Seed Non-Halation L Ortho 
UP ate Eee ae Standard Orthonon 
Eastman S C Ortho Seed L Ortho 
Eastman Post Card Standard Post Card 
Eastman Lantern Standard Lantern Slide 


Eastman Universal 


Slide (Regular, Slow) 
(Regular, Slow) Seed Lantern Slide 
Eastman X-Ray Seed X-Ray 
W. W. Panchromatic Seed Panchromatic 


376 


100% 
80% 
150% 
5% 
26% 
80% 


90% 
30% 


80% 


80% 
32% 
3% 


27% 


Index 


Acid Bath for Platinotype, 278. 
Acid Fixing Bath, 124. 

Acrol, 91. 

Activol, 109. 

Additive Filters, 344. 

Adurol, 91. 

Agfa Colour Plate, 349. 
Albumen Sensitiser, 351. 
Alcohol, 21. 

Alcohol, Denatured, 21. 
Alcohol, Methyl, 21. 

Alkaline Amidol, 93. 

Alkaline Fixing Bath, 123. 
Alkaline Toning Bath, 176. 
Altitude Exposures, 72. 

Alum Bath, 252. 
Alum-Gold-Hypo Toning, 235. 
Alum-Hypo Toning, 234. 
Alum-Sugar-Hypo Toning, 234. 
Aluminium, Blackening, 6. 
Aluminium Flashlights, 342. 
Alums as Hardeners, 129. 
Amidol, 91. 

Amidol, Alkaline, 93. 
Amidol-Pyro, 93. 

American Photography Expo- 
sure Tables, 51. 
American Photography Plate 

Speeds, 55. 
Ammonia Fixing Bath, 125. 
Ammonium Persulphate 
ducer, 146. 
Ammonium Sulphide Toning, 
236. 
Amount of Flashlight Powder, 
342. 
Angle of View Tables, 45. 
Aniline Process, 318. 
Aniline Black Process, 320. 
Anthracotype Process, 317. 
Aquarelle Printing, 306. 
Arabin Gum-Bichromate, 256. 
Asphalt Backing, 32. 


Re- 


Atomic Weights, 373. 
Autochrome Plates, 345. 
Autochrome Developers, 345. 
Autochrome Intensification, 348. 
Autochrome Reverser, 347. 
ee! Second Developer, 
347. 
Autochrome, Varnishing, 348. 
Azol, 109. 


Backgrounds, 1. 

Backing, Asphalt, 32. 
Backing, Black, 33. 
Backing, Caramel, 31. 
Backing, Chrevetot’s, 33. 
Backing, Collodion, 32. 
Backing, Cornu’s, 32. 
Backing, Oxgall, 34. 
Backing Plates, 31. 
Backing Sheets, 34. 
Backing, Soap, 34. 
Bartolozzi Tones, 182. 
Beach’s Developer, 113. 
Beck Meter, 75. 
Belitzski’s Reducer, 141. 
Bichromate Reducer, 142. 
Binding Lantern Slides, 330. 
Bitumen Process, 353. 
Black Backing, 33. 

Black for Cameras, 6 
Black Varnish, 154. 
Blackening Aluminium, 6. 
Blackening Brass, 4. 
Blackening Wood, 4. 
Bleach, Bromoil, 303. 
Blocking-out Medium, 157. 
Blue-green & Green Sensitisers, 


Blue Prints, Toning, 260. 
Blue Process, 258. 
Bottles, Ink for, 6. 
Brass, Blackening, 4. 
Brasses, Memorial, 3. 


377 


378 PHOTOGRAPHIC FACTS AND FORMULAS 


Bromide Paper, 199. 

Bromide Paper Development, 
199. 

Bromide Paper Developers, 200- 
202. 


Bromide Paper Exposure, 199. 

Bromide Paper Factorial De- 
velopment, 202. 

Bromide Paper Speeds, 67. 

Bromide Print for Bromoil, 311. 

Bromide v. Platinotype, 294. 

Bromoil Bleach, 303. 

Bromoil Bromide Print, 311. 

Bromoil Presses, 310. 

Bromoil Process, 302. 

Bromoil, Rubbing, 307. 

Bromoil Transfers, 306, 312. 

Burroughs - Wellcome Plate 
Speeds, 55. 


Cameras, Blackening, 6. 

Caramel Backing, 32. 

Carbon Tissue, Making, 250. 

Carbon Process, 249. 

Carbro Process, 299. 

Carmine Toning, 244. 

Casein Paper, 195, 337. 

Celluloid Varnish, 155. 

Cements, 8. 

Ceric Sulphate Reducer, 143. 

Certinal, 109. 

Chemical Tables, 368. 

Chlorate - Magnesium  Flash- 
lights, 340. 

Chrevetot’s Backing, 33. 

Chrome Alum Fixing Bath, 124. 

Chromium Intensifier, 134. 

Citol, 109. 

Cleaning Glass, 8. 

Opec) Photogravure Plate, 
356. 

Cleaning Zinc & Copper, 351. 

Clearing Baths, 128. 

Coating Carbon Tissue, 250. 

Cobalt Toning, 228. 

Cobalt-Iron Process, 268. 

Coefficient, Temperature, 78. 

Coins, Photographing, 3. 

Cold Bath Platinotype, 281. 


Cold oe Sepia Platinotype, 
279 


Cold Bath Process, 277. 
Cold Varnishes, 150, 154. 
Collodio - Chloride Emulsion, 


160. 

Collodio-Chloride Prints, Flat- 
tening, 169. 

Collodion Backing, 32. 

Collodion Transfer, 252. 

Colloidal Sulphur Toning, 235. 

Collotype, 354. 

Colour Photography, 344. 

Columbian Methanol or Spirit, 
ahs 

Combined Developing & Fix- 
ing, 85. 

agers Toning & Fixing, 
178. 

Combining Lenses, 43. 

Comparison of Plate Speeds, 69. 

Conjugate Foci, 49. 

Continental Plate Speeds, 61. 

Seep Developer, Cramer, 

Conversion of Weights & Meas- 
ures, 360 

Copper Bromo-Iodide Intensi- 
fier, 139 

Copper Ferrocyanide Intensi- 
fier, 137. 

Copper Half-Tone Enamel, 353. 

Copper, Scum Remover, 354. 

Copper-Silver Intensifier, 135. 

Copper-Tin Intensifier, 136. 

Copper Toning, 216 

Cornu’s Backing, 32. 

Cor ead for Spectacle Lene 
4 


Crystal Varnish, 156. 

Crayon Fixative, 157. 

Cupric Chloride Reducer, 144. 
Cyanotype Process, 258. 
Cyanotype Transparencies, 261. 


Damp-proof Glue, 9. 
Debenham’s Reducer, 141. 
Denatured Alcohol, 21. 
Depth of Focus, 42. 


INDEX 


Depth of Focus Scale, 41. 
Desensitising Plates, 28. 
Devarnishing Negatives, 154. 
cee Sepia Platinotype, 
Developer, Acrol, 91. 
Developer, Activol, 109. 
Developer, Alkaline Amidol, 93. 
Developer, Amidol, 91. 
Developer, Amidol-Pyro, 93. 
Developer, Azol, 109. 
Developer, Beach’s, 113. 
Developer, Certinal, 109. 
Developer, Citol, 109. 
Developer, Contrast, 101. 
Developer, Diogen, 94. 
Developer, Eastman Film, 100, 
103, 119. 
Developer, Edinol, 94. 
Developer, Eikonogen, 95. 
Developer, Elon, 95, 101. 
Developer, Ferrous Oxalate, 95. 
Developer, Glycin, 98. 
Developer, Hydrochinon, 99. 
Developer, Kachin, 109. 
Developer, Kalogen, 109. 
Developer, Kodelon, 101. 
Developer, Lantern Plate, 331. 
oper. Metol-Hydrochinon, 
3 


Developer, M. P., 100. 
Developer, Motol, 101. 
Developer, Neol, 107. 
Developer, Ortol, 107. 
Developer, Paramidophenol, 108. 
Developer, Paramol, 109. 
Developer, Paranol, 109. 
Developer, Paraphenylendiamin, 
109 


Developer, Pyrocatechin, 109. 
Developer, Pyro, “B. J.,” 112. 
Developer, Pyrogallol, 111. 
Developer, Pyro-Caustic, 112. 
Developer, Pyro-Acetone, 113. 
Developer, Pyro-Metol, 119. 
Developer, Rodinal, 108. 
Developer, Standard H. & D., 
112. 
Developer, Tank, 113. 


379 


Developer, Tozol, 122. 

Developers, 91. 

Developers, Tank, 91. 

Tie CPne Autochromes, 345, 
347. 

Developing & Fixing Combined, 
85 


Developing Line Prints, 264. 
Developing P. O. P., 183. 
Developing-out Papers, 204. 
Development, 76. 

Development Factors, 76. 
Development, Factorial, 76. 
Development Papers, 204. 
Pepa lget et Papers, Artura, 


Development Papers, Athena 
Old Master, 206. 

Development Papers, Azo, 211. 

Development Papers, Cyko, 209. 

Development Papers, Develop- 
ers, 204. 

Development Papers, Develop- 
ers, Non-Abrasion, 205. 
Development Papers, Defender, 

2IZ5213: 
Development Papers, Enlarging 
Cyko, 210 
Development Papers, Etching 
Brown, 206. 
Sie iat Papers, Gevaert, 
3 


Gevaert 


Haloid, 


Development Papers, 
Nova-Gas, 214. 
Development Papers, 

208 


Development Papers, Kodelon 
Developer, 207. 

Development Papers, Mimosa 
Verotype, 210. 

Development Papers, Noko, 210. 

Development Papers, Pyro De- 
veloper, 205. 


Development Papers, Roylon 
Developer, 207. 

Development Papers, Short 
Stop: Bath, 215. 

Development Papers, Tozol 
Bath, 207. 


380 PHOTOGRAPHIC FACTS AND FORMULAS 


Development Papers, Velox, 
208. 

Development Papers, Velvet 
Green, 210. 

Development Papers, Vitava, 
205. 

Development Papers, Vittex, 


Development, Stand, 80. 
Development-Sulphide Toning, 
245 


Development, Thermo, 77. 
Dextrine Mountant, 325. 
Dextrine-Gum Mountant, 325. 
Diagonals of Plates, 46. 
Diagram Lantern Slides, 330. 
Diamond Cement, 9. 
Diaphragm Apertures, 44. 
Diaphragm Systems, 74. 
Diazotype Process, 320. 
Dichroic or Green Fog, 129. 
Diogen, 94. 
Direct Negatives, 15. 
Direct Prints on Zinc, 358. 
Direct Sulphide Toning, 234. 
Distribution of Spectrum Col- 
ours, 23. 
Dry Mounting, 327. 
nena & Metric Systems, 
364. 
Duration of Flash, 343. 
Dusting-On, Pepper, 316. 
Dye Intensification, 140. 
Dyeing Fish-Glue Prints, 353. 


Eastman Film Developers, 100, 
103, 119. 

Eastman Plates, 376. 

Eder’s Reducer, 144. 

Edinol, 94. 

Effect of Stop Aperture, 71. 

Eikonogen, 95. 

Elconal, 109. 

Eliminators, Hypo, 126. 

Elon, 95. 

avis C. C. Printing-out, 


Emulsion, Printing-out, 173. 
Enamel for Zinc, 352. 


Endemann’s Process, 320. 

Enlarging, Exposures in, 335. 

peepee Exposures Variation, 
2 


Enlarging & Reducing Table, 
334. 

Etching Bath, Zinc, 353. 

Etching, Machine, 354. 


ar: Photogravure Plate, 

378 

Exposure, 51, 60. 

Exposure, Effect of Altitude, 
2 


Exposure in Enlarging, 335. 
Exposure Meters, 75 
Exposure Meter Paper, 75. 
Exposures for Interiors, 73. 
Exposures, Pinholes, 48. 
Exposures in Reducing, 335. 
Exposure Tables, American 
Photography, 51. 


F Values, Variation of, 71. 
Fabrics, Fireproofing, 5. 
Fabrics, Sensitising, 195. 
Factorial Development, 76. 
Factorial Development of Bro- 
mide Papers, 202. 
Factors, Development, 76. 
Farmer’s Reducer, 145. 
Feertype Process, 320. 
Ferric Oxalate Making, 274. 
Ferric Reducers, 145. 
Ferrogallic Process, 263. 
Ferroprussiate Process, 258. 
Ferrous Oxalate, 95. 
Film Developers, 100. 
Films, Stripping, 157. 
Filters, Additive, 344. 
Filters, Orthochromatic, 29. 
Filters, Three-Colour, 344. 
Final Support, 253. 
Fireproofing Fabrics, 5. 
Fish-Glue Prints, Dyeing, 353. 
Fish-Glue Sensitiser, 351. 
Fixative for Prints, 157. 
Fixing, 123. 
Fixing, Plain Bath, 123. 
Fixing, Alkaline Bath, 123. 


INDEX 


Fixing, Acid Bath, 124. 

Fixing, Acid-Alum Bath, 124. 

Fixing, Acid-Chrome Alum 
Bath, 124. 

eae Rapid Ammonia Bath, 
12 


Fixing P, O: P., 179. 

Fixing and Clearing, 123. 

Flash Candles, 340. 

Flashlights, 339. 

Flashlights, Aluminium, 342. 

Flashlight Candles, 340. 

Flashlight, Chlorate, 340. 

Flashlight, Duration of, 343. 

Flashlight, Magnesium-Nitrate, 
339. 

Flashlights, Orthochromatic, 
341. 

Flashlights, Perchlorate, 340. 

Flashlight Sheets, 340. 

Flashlight, Slow-Burning, 341. 

Flashlights, Using, 339. 

Flashlights, Weight Needed, 
342. 

Flash Sheets, 340. 

Flattening C. C. Prints, 169. 

Focal Length of Lens, 35. 

Foci, Conjugate, 49. 

Focus & Optics, 35. 

Focus, Depth of, 42. 

Focus Scale, Depth of, 41. 

Focusing Rules, 43. 

Fog, Dichroic, Red or Green, 
129 


Fourtier’s Reducer, 144. 
Fraunhofer Lines, 
lengths, 22. 


Wave- 


Gaslight Papers, 204. 

Gelatine Mountant, 326. 

Gelatine Mountant, Liquid, 326. 

Gelatine P. O. P., 173. 

Glass, Cleaning, 8. 

Glass, Matting, 7. 

Glass, Photographing Objects 
Under, 4. 

Glass Safelights, 17. 

Glass, Silvering, 9. 

Glassware, Photographing, 3. 


381 


Glue, 9. 

Glycin, 98. 

Gold & Platinum Toning, 228. 

Gold & Uranium Toning P. O. 
Pal e2, 

Gold Residues, 126. 

Graining Copper, 351. 

ene Photogravure Plate, 
356. 

Greasy Ink Process, 265. 

Green Safelights, 19. 

Green Tones, 227. 

Green & Yellow Sensitisers, 24. 

Green & Yellow-Orange Sensi- 
tisers, 25. 

Ground Glass Substitutes, 7. 

Gum-Bichromate Pigments, 255. 

Gum-Bichromate Process, 255. 

Gum-Iron Process, 261. 


H. & D. Standard Developer, 
eZ 


Half-Tone Enamel, 353. 

Hard Enamel for Zinc, 352. 

Hardening Agents, Alum, 129. 

Hardening Baths, 127. 

Meets Harsh Negatives, 
147, 

Cosa eh ha Harmonising, 
4 


Harvey Plate Speeds, 55. 

Hot Bath Platinotype, 280. 
Hot Varnishes, 150. 
Hydrochinon, 99, 
Hypersensitising Plates, 26. 
Hypo Eliminators, 126. 

aheee Ferricyanide Reducer, 


Hypochlorite Reducer, 141. 


Indirect Sulphide Toning, 238. 

Ink for Bottles, 6. 

Ink Process, 263. 

Inking-Up Line Work, 352. 

Intensification, 130. 

Intensifier, Agfa, 133. 

Intensifier, Chromium, 134. 

Intensifier, Copper Bromo- 
iodide, 139. 


382 PHOTOGRAPHIC FACTS AND FORMULAS 


Intensifier, Copper Ferrocyan- 
ide, 137 
Intensifier, Copper-Silver, 135. 
Intensifier, Copper-Tin, 136. 
Intensifier, Dye, 140. 
Intensifier, Eder’s, 132. 
Intensifier, Formalin, 132. 
Intensifier, Lead, 138. 


Intensifier, Mercuric Iodide, 
133; 
Intensifier, Mercuric Sulpho- 


cyanide, 133. 
Intensifier, Mercury, 130. 
Intensifier, Monckhoven’s, 131. 
Intensifier, Quinone, 138. 
Intensifier, Schlippe’s Salt, 132. 
Intensifier, Silver-Cyanide, 131. 
Intensifier, Stannous Tartrate, 
132) 
Intensifier, Uranium, 137. 
Intensifying Autochromes, 348. 
Intensifying Carbon Transpar- 
encies, 253. 
Intensifying Platinotypes, 287. 
Interior Exposures, 73. 
Iodide-Hypo Reducer, 143. 
Iodo-Cyanide Reducer, 143. 
Iron or Cyanotype Toning, 220. 
Iron Processes, 258 
Itterheim’s Process, 316. 
Ivory Final Support, 253. 


Kachin, 109. 

Kallitype Process, 270. 
Kalogen, 109. 
Kodelon, 101. 


Lainer’s Reducer, 143. 
Lantern Plate Speeds, 68. 
Lantern Screen, Flexible, 6. 
Lantern Slides, 330. 

Lantern Slides, Binding, 330. 
Lantern Slide Developers, 331. 
Lantern Slide Diagrams, 330. 
Lantern Slide Sizes, 330. 
Lantern Slide Spotting, 330. 
Latitude Light Tables, 52. 
Lead Intensifier, 138. 
Lead-Iron Toning, 225. 


Lead Toning, 225. 

Leather, Sensitising, 195. 

Lens Focus, 35. 

ee Bec Stereoscopic, 


Lenses, Care of, 50 

Lenses, Combining, 43. 

Light Tables for Latitudes, 52. 

Line Drawings from Prints, 14. 

Line Prints, Developing, 352. 

Line Prints, Inking-Up, 352. 

Line Sensitiser, 351. 

Liquid Glue, 9. 

Liquid Safelights, 16. 

Liver of Sulphur Toning, 236. 

Local Development, Platino- 
type, 286. 

Lumiére’s Reducer, 143, 147. 


Machine Etching, 354. 
Machinery, Photographing, 3. 


Magnesium - Chlorate Flash- 
lights, 340. 
Magnesium-Nitrate Mixtures, 


339. 
Magnesium, Underground, 342. 
Making Carbon Tissue, 249. 
Making Ferric Oxalate, 274. 
Marine Glue, 9. 
Matt Lac Plain Papers, 190. 
Matt Varnishes, 150. 
Matting Glass, 7. 
Mechanical Reduction, 148. 
Medium, Blocking-out, 157. 
Medium, Retouching, 156, 157. 
Memorial Stones & Brasses, 


Mercury Intensifiers, 130. 

Mercury-Cyanide Reducer, 144. 

Mercury Sulphide Toning, 242. 

Mercuric Iodide Intensifier, 133. 

Mercuric Sulphocyanide Inten- 
sifier, 133. 

Mercuro-Uranotype, 293. 

Meter, Beck, 75. 

Meter, Imperial, 75. 

Meter, Watkins, 75. 

Meter Wynne, 75. 

Meters, Exposure, 75. 


INDEX 


Metol, 101. 

Metol Poisoning, 102. 

Metol-Hydro Developer, 103. 

Methanol, Eagle, 21. 

Methyl Alcohol, 21. 

Metric & Duodecimal Equiva- 
lents, 364. 

Mimosa Aurotype P. O. P., 187. 

Molybdenum Toning, 231. 

Monckhoven’s Intensifier, 131. 

M. P. Developers, 100. 

Motol, 101. 

Mountants, 325. 

Mountants, Dextrine, 325. 

ea Dextrine & Gum, 
325. 

Mountants, Gelatine, 326. 

Mountants, Liquid Gelatine, 326. 

Mountants, Starch-Gelatine,326. 

Mountants, Starch Paste, 327. 

Mounting, Dry, 327. 

Mounting, Photogravure Re- 
sist, 356. 

Mounting Stereo Prints, 328. 

Moving Objects, Shutter 
Speeds, 72. 


Namias’ Reducer, 142. 

Negatives, Devarnishing, 154. 

Negatives, Direct, 15. 

Negrographic Process, 316. 

Neol, 107. 

Night Photography, 73: 

Nitrate-Magnesium Flashlights, 
339. 

Non-actinic Paper, 20. 

Non-Achromatic Lens Correc- 
tion, 47. 


Objects Under Glass, 
graphing, 4. 
Oxgall Backing, 34. 
Oilograph Process, 306. 
Oil Printing, 305. 
Oil & Bromoil Process, 302. 
Opal Glass Final Support, 253. 
Orthochromatic Filters, 29. 
Orthochromatic Flashlights, 
341. 


Photo- 


383 


Orthochromatic Photography, 
Orthochromatising Plates, 24. 
Ortol, 107. 

Ozobrome Process, 297. 
Ozotype Process, 295. 


Paget Colour Plate, 348. 
Palladiotype, 282, 293. 
Palladium Toning, 182. 
Panchromatic & Red Sensitis- 
ers; 25, 
Panchromatising Plates, 27. 
Paper for Exposure Meters, 75. 
Paper, Non-actinic, 20. 
Papers, Developing-out, 204. 
Paramidophenol, 108. 
Paramol, 109. 
Paranol, 109. 
Paraphenylendiamine, 109. 
Pellet’s Process, 261. 
Pepper Dusting-on Process, 316. 
Percentage Solutions, 362. 
Permanganate Reducer, 142. 
Phosphate of Silver Paper, 169. 
Photography at Night, 73. 
Photogravure, 356. 
AEA Cleaning Plate, 
356. 
Photogravure 
tiGtis 304, 
Photogravure 
356 


Etching Solu- 
Graining Plate, 


Photogravure, Setting Grain, 
356 


Photogravure Mounting Resist, 
356. 


Photogravure Varnishing, 357. 

Photolithography, 357. 

Photomechanical Processes 351) 

pee for Gum-Bichromate, 
255: 

Pinhole Exposures, 48. 

Plain Fixing Bath, 123. 

Plain Papers, 189. 

Plain Papers Casein, 195. 

Plain Papers, Printing, 192. 

Plain Papers, Resin-sized, 193. 

Plain Papers, Sensitising, 191. 


384 PHOTOGRAPHIC FACTS AND FORMULAS 


Plain Papers, Sepia-iron, 194. 
Plain Papers, Sizing, 189. 
Plain Papers, Toning, 192, 
Plate Backing, 31. 
Plates, Desensitising, 28. 
Plate Diagonals, 46. 
Plates, Hypersensitising, 26. 
Plates, Orthochromatising, 24. 
Plates, Panchromatising, 27. 
Plate speeds, 55. 
Plate Speeds, American Photo- 
graphy, 55. 
Plate Speeds, Burroughs-Well- 
come, 55. 
Plate Speeds, Comparison, 69 
Plate Speeds, Continental, 61. 
Plate Speeds, Harvey, 55. 
Plate Speeds, Watkins, 55. 
Plate Speeds, Wynne, 55. 
Platinotype, Cold Bath, 281. 
Platinotype, Developers, 278. 
Platinotype, Hot Bath, 280. 


Platinotype, Local Develop- 
ment, 286. 

Platinotype, Print-Out Sepia, 
0 


Platinotype Process, 274. 
Platinotype v. Bromide, 294. 
Platinotypes, Intensifying, 287. 
Platinotypes, Restoring, 291. 
Platinotypes, Toning, 288. 
Platinotypes, Varnishing, 292. 
Platino-Uranotype, 293. 
Platinum Acid Bath, 278. 
Platinum Paper, Sizing, 274. 
Platinum-in-Developer Process, 
283. 
Platinum Print-Out Paper, 284. 
ae Process, Cold Bath, 
Platinum Residues, 126, 292. 
Platinum Toning, 229. 
Platinum Toning P. O. P., 180. 
Platinum & Gold Toning P. O. 
P 18h 
Playertype Process, 267. 
Poisoning, Metol, 102. 
Powder Process, 314. 
Presses for Bromoil, 310. 


Primuline Process, 320. 

Printer’s Ink Process, 265. 

Print Varnish, 154. 

Print-Out Platinum Paper, 284. 

te Bromide Paper, 
171. 

Printing-Out Papers, 173. 

Printing-Out Papers, Develop- 
ing, 183. 

aera Papers, Disco, 


Printing-Out Papers, Eastman 
Solio, 186. 

Printing-Out Papers, Printing, 
176 


Printing-Out Papers, Toning, 
176. 


Prints, Line Drawings from, 14. 
Prints on Zinc, Direct, 358. 
Process Pyro Developer, 111. 
Pyro, 111. 

Pyro-Acetone, 113. 
Pyro-Amidol, 93. 
Pyro-Caustic, 112. 
Pyro-Glycerine, 111. 
Pyro-Metol, 121. 
Pyro-Potash, 113. 
Pyro-Soda, 112. 

Pyro-Seda, “Baja ati: 
Pyro Tank Developers, 113. 
Pyrocatechin, 109. 
Pyrogallol, 111. 


Quick-Drying Sensitiser, 251. 
Quinone Intensifier, 138. 
Quinone Toning, 240. 


Ratio Aperture, 44. 

Red Chalk Tones, 182, 244. 

Red Tones, 178. 

Reducers, 141. 

Reducer, Ammonium Persul- 
phate, 146. 

Reducer, Belitzski’s, 141. 

Reducer, Bichromate, 142. 

Reducer, Ceric Sulphate, 143. 

Reducer, Cupric Chloride, 144. 

Reducer, Debenham’s, 141. 

Reducer, Eder’s, 144. 


INDEX 


Reducer, Farmer’s, 145. 
Reducer, Ferric Oxalate, 141. 
Reducer, Fourtier’s, 144. 
Reducer, Hypochlorite, 141. 
ares Hypo - Ferricyanide, 
Reducer, Iodide-Hypo, 143. 
Reducer, Iodo-Cyanide, 143. 
Reducer, Mercury-Cyanide, 144. 
Reducer, Permanganate, 142. 
Reducer, Quinone, 147. 
Reducer, Spiller’s, 144. 
Reducing, Exposures in, 335. 
Reducing Sulphided Prints, 245. 
Reduction, Mechanical, 148. 
Residues, 125. 
Residues, Gold, 126. 
Residues, Platinum, 126, 292. 
Restoring Platinotypes, 291. 
Retouching Varnish, 156. 
Reverse Process, 358. 
Reversing Autochromes, 347. 
Rodinal, 109. 
Rules for Focusing Hand Cam- 
eras, 43. 


Safelights, Glass, 17. 
Safelights, Green, 19. 
Safelights, Liquid, 16. 
Satista Paper, 282. 

Salted Paper, 189. 

Screen Plates, 345, 348, 349. 
Scum Remover, 354. 
Selenium Toning, 230. 
eee Paper Aurotype, 
Self-Toning Gevaert, 188. 
Self-Toning Ronix, 188. 
Sensitiser, Albumen, 351. 
Sensitiser, Fish-Glue, 351. 


Sensitisers, Blue - Green & 
Green, 24. 

Sensitisers, Green & Yellow, 24. 

Sensitisers, Green, Yellow, 
Orange, 25. 

Sensitisers, Panchromatic & 
Red, 25. 


Sensitiser, Quick-Drying, 251. 
Sensitising Carbon Tissue, 251. 


385 


Bae noes Leather, Fabrics, 

195. 

Sensitising Wood, 196. 

eee Platinotype, Cold Bath, 
9 


Fae -Platinotype, Developed, 

85. 

Sepia, Print-Out Platinotype, 
290. 

Setting Photogravure Grain, 
356 


Sheets, Backing, 34. 

Short Stop Bath, 215. 

Shutter Speeds for Moving Ob- 
jects, 72. 

Shutter Speeds, Timing, 51. 

Silver Bromide P. O. P., 171. 

Silver Phosphate Paper, 169. 

Silver Printing Processes, 160. 

Silver-Potassio-Cyanide Inten- 
sifiers, 131. 

Silvering Glass, 9. 

Silverware, Photographing, 3. 

Single Transfer Paper, 251. 

Sizing Platinum Paper, 274. 

Slides, Lantern, 330. 

Slow-Burning Flashlights, 341. 

Sobacchi’s Process, 317. 

Solar Printing, 336. 

Soap Backing, 34. 

Solutions, Percentage, 362. 

Solution, Waxing, 252. 

Spectacle Lenses, 47. 

Spectrum Colours, Distribution 
Glezo: 

Speeds, Bromide Paper, 67. 

Speeds, Lantern Plate, 68. 

euccds Thermo Development, 


Spiller’s Reducer, 144. 
Spirit, Columbian, 21. 
Spotting Lantern Slides, 330. 
Stand Development, 80. 
Starch-Gelatine Mountant, 326. 
StarchmePaste, 32/7: 
Stereoscopic Work, 328. 
Stop Aperture Effect, 71. 
Stop Aperture Systems, 74. 
Stripping Films, 157 

Studio & Workroom, 1, 


386 PHOTOGRAPHIC FACTS AND FORMULAS 


Sulphide - Developer Toning, 
241. 

Sulphide-Ferricyanide Toning, 
236. 

Sulphide-Schlippe’s Salt Ton- 
ing, 244. 

Sulphide Toning, 234. 

Sulphocyanide Toning Bath, 
Ly 


yf 
Sulphur Toning, 247. 
Support, Flexible Temporary, 
251 


Symbols, Molecular Weights, 
368. 


Table, Enlarging & Reducing, 
334 


Tank Developers, 88. 
Telephoto Formulas, 47. 
Temperature Co-Efficient, 78. 
Temporary Support, 251. 
Thermo Development, 77. 
alae Development Speeds, 
Thermometer Scales, 366. 
Thiocarbamide-Sulphide 
ing, 238. 
Thiomolybdate Toning, 240. 
Thiostannate Toning, 240. 
Three-Colour Filters, 344. 
Timing Shutter Speeds, 51. 
Toning Blue Prints, 260. 
Toning Bromide & Gaslight 
Prints, 216. 
Toning by Redevelopment, 232. 
Toning Platinotypes, 288. 
Toning 2) Oo Po 176. 
Toning Bath, Alkaline, 176. 
Tome Bath, Sulphocyanide, 


Ton- 


Toning & Fixing Bath, Com- 
bined, 178. 

Tozol, 122. 

Transfer Paper, Single, 251. 

Transfers, Bromoil, 306. 

Transfer with Collodion, 252. 

Transparencies, Blue, 261. 

Transparencies, Carbon, 253. 

Transparencies, Cyanotype, 261. 

True-to-Scale Process, 265, 


Underground Magnesium Work, 
342. ' 

Uranium & Iron Toning, 227. 

Uranium Toning, 219. 

Uranium Toning P. O. P., 182. 

Uranium Intensifier, 137. 

Using Flashlights, 339. 


Vanadium Toning, 222. 

Vandyke Process, 358. 

Variation of F Values, 71. 

Variation of Enlarging Expo- 
sures, 72. 

Varnishes, 150. 

Varnish, Black, 154. 

Varnish, Celluloid, 155. 

Varnish, Crystal, 156. 

Varnish, Cold, 150, 154. 

Varnish, Hot, 130; 

Varnish, Matt, 153. 

Varnish, Print, 154. 

Varnish, Retouching, 156. 

Varnish, Zapon, 155. 

Varnishing Autochromes, 348. 

Maer Photogravure Plate, 

Varnishing Platinotypes, 292. 

View Angles, 45. 


Watkins Plate Speeds, 55. 

Watkins-Powers Numbers, 49. 

Wave - Lengths Fraunhofer 
Lines, 22. 

Waxing Solution, 252. 

Weights & Measures, 1, 360. 

Weights & Measures Conver- 
sion, 360. 

bec a & Measures Tables, 

Willis’s Process, 318. 

W. P. Numbers, 49. 

Wood, Blackening, 4. 

Wood Final Support, 253. 

Wood Sensitising, 196. 

ae Panchro Developers, 

Wynne Plate Speeds, 55. 


Zapon Varnish, 155. 
Zinc & Copper, Cleaning, 351, 
Zinc, Etching Baths, 353,45 


Ansco Photoproducts, inc. 
BINGHAMTON, N. Y. 


Manufacturers of: 


Ansco Speedex Film—for all roll-film cameras. 
The film in the red box with the yellow band. Extra 
speed, extra latitude, more good negatives under a 
wider range of light conditions. 


Ansco Cameras—priced from $1 to $75, with 
many models making a strong appeal to the expert 
and discriminating photographer. Catalog at your 
dealer’s or by mail. 


Noko Paper—for amateur finishing and commer- 
cial work. Built to meet the requirements of photo- 
finishing plants. A quality product at attractive 
prices. 


Commercial Cyko—a fast contact paper for com- 
mercial photographers and amateurs. 


Enlarging Cyko—the finest projection paper made. 
For enlargements of true professional quality, with 
full scale of tones from rich luminous blacks to pearly 
highlights. Very easy to work. 


Professional Cyko—The standard of uniformity 
and quality for the best grade of studio work. 


Ansco Portrait Film—a cut film of high speed and 
quality to meet the most exacting studio requirements. 


Film and camera dealers everywhere. Paper stock houses 
at convenient points. Price lists and complete 
information on request. 


ANSCO PHOTOPRODUCTS, INC. 
Binghamton, N. Y. 





Off 


Quality 
for 


| vert speed and _ clearness, 





Means 
Good 


Roll Films 
















orthocromatic, anti-halo, non- 


Film Packs curling 

Plates a plate for every purpose 

Color Plates for pictures in natural colors 

Process and Intaglio for Reproduction and Engraving 

Plates and Films Plants 

Portrait Films an ideal Agfa-emulsion for por- 
traiture on a heavy celluloid 
base 

Developers Rodinal, Metol, Glycin, Amidol, 
etc. 


Blitzlicht (Flashlight) producing the most intense light, 
but hardly any smoke, noise- 
less combustion 


Agfa Flashlight Lamps Amateur and professional sizes 


AGFA PHOTO HANDBOOK 
by Dr. M. ANDRESEN | 


300 p. text, fully illustrated, with useful information. 


Ask for illustrated catalog and price list, and special information 
leaflets on Color Plates, Light Filters and Negative Material for 
process work. 


Ay fee Prodsscld , tne. 


114-116 East 13th Street, New York City, N. Y. 








A Bausch & Lomb Lens 
For Every Purpose 





TESSAR Ie, £: 4.5—Master of speed and light. Un- 
excelled for ultra rapid work, portraits, groups, land- 
scapes, etc. “he most universal of the unsymmetrical 
anastigmat lenses. 


TESSAR IIb, f: 6.3—For general use on hand-cameras, 
for groups, landscapes, commercial photography, en- 
largements, etc. Similar to TESSAR Ic, but more 
compact and with less speed. 


PROTAR VlIla, f£: 6.3—A rapid, convertible anastig- 
mat lens, adapted for landscapes, architecture, por- 
traits, groups, etc. For purposes requiring long 
focus, medium speed and narrow angle. 


PROTAR IV and V, f: 12.5 and f£: 18—Rapid ana- 
stigmat wide angle lenses of short focus, for archi- 
tectural and interior work, and groups. 


PLASTIGMAT, f: 5.6—For artistic and blended 
photographs, including portraits, landscapes and 
architectural subjects. Produces the desired soft 
effect at full aperture. 


There is a Bausch & Lomb Photographic Lens for every 
purpose. Send for your copy of our illustrated cata- 
log, “What Lens Shall I Buy?” which outlines the 
requirements of different branches of photography 
and recommends the proper lenses. 


pausch 8 lomb Optical ©. 
238 FREEMAN STREET, ROCHESTER, N. Y. 
New York Chicago Boston San Francisco Washington London 


GOERZ | 


PHOTOGRAPHIC LENSES of high grade: the old ° 
reliable Dagor, f: 6.8, for hand cameras and commercial 
work; wide angle Dagor, f: 9, with plenty of light for 
focusing (new) ; Dogmar, f: 4.5-f: 5.5, the ideal speed 
lens, the single lenses give large size images; Syntor, 
f: 6.8 and Tenastigmat, f: 6.3, moderate speed, inex- 
pensive hand camera anastigmats; Portrait Hypar, 
f: 4.5, the portrait lens without harsh wire edge sharp- 
ness; Kino-Hypar, f: 3 and f: 3.5, for movie cameras; 
Kino-Telegor, f: 6.3, for telephoto movie effects; 
Telegor, f£: 6.3, a fast working telephoto lens for re- 
flecting cameras, for sports and naturalist photography; 
Artar and Gotar Lenses for the photo-engraver; 
Compound Shutters, etc. 


OUR CAMERA LINE comprises Roll Film 
Tenax; Pocket Tenax for plates and film packs; Taro 
and Manufoc Tenax, with double extension for plates 
and film packs; Ango Focal Plane Cameras; Stere- 
oscopic Cameras; Hahn-Goerz Motion Picture 
Cameras and Projectors. 


Complete line of accessories, plate-holders, film pack 
adapters, kits, etc.—carried in stock. 


Other products are Binoculars, Telescopes, Polar- 
iscopes, Barometers and Scientific Instruments of 
varied types. 


Information and Printed Matter on Request 


C. P, GOERZ AMERICAN OPTICAL COMPANY 


317AF East 34th Street, New York City 





GEVAERT 


PAPERS and PLATES 


PAPERS 


RONIX—Daylight Printing, Self Toning 
NOVAGAS—Contact, Prints, Any Artificial Light 
VITTEX—Contact or Enlarging, Artificial Light 
NOVABROM—Enlarging, a Bromide for All Work 
ORTHOBROM—Bromide for Pictorial Work 
BROMOIL—Special for This Process 

PROOF PAPER 


PLATES 


Sensima sooHD Portraiture 

Sensima Ortho sooHD Portrait, Press, Landscape 
Sensima Ortho Anti Halo 500HD All Around, Ortho 
Sensima Mat (Matte Emulsion) s500HD Portraiture 
Special Sensitive 4ooHD All Around Work 
Orthochromatic 400HD Used With a Filter 

Ortho Anti Halo 250HD Used With a Filter 
Filtered Ortho 250HD No Filter Needed With This Plate 
Ordinary 

Process 

Ortho Process 

Lantern Slides, Black 

Lantern Slides, Warm Tone 


Fast plates should be developed 50% longer than slow 
plates. 


The Sensima Mat Plate saves time on account of its 
matte surface. 


Filtered Ortho Plates have incorporated with the emul- 
sion a filtering medium which holds back the ultra violet 
rays but admits the yellows and greens. 


VOHHQHHNHNY HO RHAGCUONN QHHNPHOQOHORN UCUMNHHHNZhn 





THE GEVAERT COMPANY OF AMERICA‘ Inc. 
423 to 439 WEST 55tH STREET 
NEW YORK 
Chicago Branch—Geo. W. Mackness Co., 180 N. Wabash Ave. 








THE LARGEST 


and Most Comprehensive 


CATALOGUE 


Ever Offered to 
CAMERA ENTHUSIASTS 


Your copy, 228 pages, is ready. Send in your name and 
address, right now, while you have this notice before you. 


CAMERAS, KODAKS, LENSES & SUPPLIES 


of every description, Domestic and Foreign, are listed 
in this Catalogue, at the very lowest possible prices. 


EVERY ITEM GUARANTEED 


Besides, you have the privilege of testing what you 
purchase, 10 days. After which time, if unsatisfactory, 
you can return and we will refund in full, or, we will 
exchange for something else you may wish instead. 


REMEMBER TOO:— 


We deal in used equipments. If you wish a used 
Camera, Kodak or Lens, send for our special bargain 
book, free on request. 


WE HAVE HUNDREDS OF 


unsolicited testimonials from customers who are 
pleased with our service as well as merchandise. We 
can do likewise for you. 


WE BUY OR TRADE OUTFITS 


Perhaps you have one you wish to trade or sell. Send 
in a complete description of it, and we will make you 
the very best offer in cash or trade. 


CENTRAL CAMERA CO. 
112 South Wabash Ave., Dept. P.F.Chicago, Illinois 








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